diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 8e3938ad6..05aafe43b 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -92,3 +92,10 @@ test-user-group:
   script:
     - cd src/yunohost
     - py.test tests/test_user-group.py
+    
+test-regenconf:
+  extends: .tests
+  stage: tests
+  script:
+    - cd src/yunohost
+    - py.test tests/test_regenconf.py
diff --git a/data/helpers.d/fail2ban b/data/helpers.d/fail2ban
index 54581483d..d8777a16d 100644
--- a/data/helpers.d/fail2ban
+++ b/data/helpers.d/fail2ban
@@ -132,7 +132,7 @@ EOF
     ynh_store_file_checksum "$finalfail2banjailconf"
     ynh_store_file_checksum "$finalfail2banfilterconf"
 
-    ynh_systemd_action --service_name=fail2ban --action=reload
+    ynh_systemd_action --service_name=fail2ban --action=reload --line_match="(Started|Reloaded) Fail2Ban Service" --log_path=systemd
 
     local fail2ban_error="$(journalctl --unit=fail2ban | tail --lines=50 | grep "WARNING.*$app.*")"
     if [[ -n "$fail2ban_error" ]]
diff --git a/data/helpers.d/systemd b/data/helpers.d/systemd
index 238f65d93..39db5db53 100644
--- a/data/helpers.d/systemd
+++ b/data/helpers.d/systemd
@@ -146,7 +146,7 @@ ynh_systemd_action() {
         for i in $(seq 1 $timeout)
         do
             # Read the log until the sentence is found, that means the app finished to start. Or run until the timeout
-            if grep --quiet "$line_match" "$templog"
+            if grep --extended-regexp --quiet "$line_match" "$templog"
             then
                 ynh_print_info --message="The service $service_name has correctly executed the action ${action}."
                 break
diff --git a/data/hooks/conf_regen/15-nginx b/data/hooks/conf_regen/15-nginx
index f8b7d8062..86c7c2438 100755
--- a/data/hooks/conf_regen/15-nginx
+++ b/data/hooks/conf_regen/15-nginx
@@ -27,7 +27,8 @@ do_init_regen() {
   ynh_render_template "yunohost_admin.conf" "${nginx_conf_dir}/yunohost_admin.conf"
 
   # Restart nginx if conf looks good, otherwise display error and exit unhappy
-  nginx -t 2>/dev/null && service nginx restart || (nginx -t && exit 1)
+  nginx -t 2>/dev/null || { nginx -t; exit 1; }
+  systemctl restart nginx || { journalctl --no-pager --lines=10 -u nginx >&2; exit 1; }
 
   exit 0
 }
@@ -125,9 +126,9 @@ do_post_regen() {
       fi
   done
 
-
-  # Reload nginx configuration
-  pgrep nginx && service nginx reload
+  # Reload nginx if conf looks good, otherwise display error and exit unhappy
+  nginx -t 2>/dev/null || { nginx -t; exit 1; }
+  pgrep nginx && systemctl reload nginx || { journalctl --no-pager --lines=10 -u nginx >&2; exit 1; }
 }
 
 FORCE=${2:-0}
diff --git a/locales/en.json b/locales/en.json
index aa1c4e4f2..3607052e3 100644
--- a/locales/en.json
+++ b/locales/en.json
@@ -74,6 +74,8 @@
     "backup_archive_name_exists": "A backup archive with this name already exists.",
     "backup_archive_name_unknown": "Unknown local backup archive named '{name:s}'",
     "backup_archive_open_failed": "Could not open the backup archive",
+    "backup_archive_cant_retrieve_info_json": "Could not load infos for archive '{archive}' ... The info.json cannot be retrieved (or is not a valid json).",
+    "backup_archive_corrupted": "It looks like the backup archive '{archive}' is corrupted : {error}",
     "backup_archive_system_part_not_available": "System part '{part:s}' unavailable in this backup",
     "backup_archive_writing_error": "Could not add the files '{source:s}' (named in the archive '{dest:s}') to be backed up into the compressed archive '{archive:s}'",
     "backup_ask_for_copying_if_needed": "Do you want to perform the backup using {size:s} MB temporarily? (This way is used since some files could not be prepared using a more efficient method.)",
@@ -91,7 +93,6 @@
     "backup_delete_error": "Could not delete '{path:s}'",
     "backup_deleted": "Backup deleted",
     "backup_hook_unknown": "The backup hook '{hook:s}' is unknown",
-    "backup_invalid_archive": "This is not a backup archive",
     "backup_method_borg_finished": "Backup into Borg finished",
     "backup_method_copy_finished": "Backup copy finalized",
     "backup_method_custom_finished": "Custom backup method '{method:s}' finished",
diff --git a/src/yunohost/app.py b/src/yunohost/app.py
index 8dce2ff38..25f856c10 100644
--- a/src/yunohost/app.py
+++ b/src/yunohost/app.py
@@ -261,6 +261,8 @@ def app_map(app=None, raw=False, user=None):
                 perm_domain, perm_path = perm_url.split("/", 1)
                 perm_path = "/" + perm_path.rstrip("/")
 
+            perm_path = perm_path if perm_path.strip() != "" else "/"
+
             return perm_domain, perm_path
 
         this_app_perms = {p: i for p, i in permissions.items() if p.startswith(app_id + ".") and i["url"]}
@@ -296,7 +298,6 @@ def app_map(app=None, raw=False, user=None):
                 continue
 
             perm_domain, perm_path = _sanitized_absolute_url(perm_info["url"])
-
             if perm_name.endswith(".main"):
                 perm_label = label
             else:
@@ -1127,11 +1128,12 @@ def app_makedefault(operation_logger, app, domain=None):
     elif domain not in domain_list()['domains']:
         raise YunohostError('domain_unknown')
 
-    operation_logger.start()
     if '/' in app_map(raw=True)[domain]:
         raise YunohostError('app_make_default_location_already_used', app=app, domain=app_domain,
                             other_app=app_map(raw=True)[domain]["/"]["id"])
 
+    operation_logger.start()
+
     # TODO / FIXME : current trick is to add this to conf.json.persisten
     # This is really not robust and should be improved
     # e.g. have a flag in /etc/yunohost/apps/$app/ to say that this is the
@@ -1289,6 +1291,8 @@ def app_ssowatconf():
                 perm_domain, perm_path = perm_url.split("/", 1)
                 perm_path = "/" + perm_path.rstrip("/")
 
+            perm_path = perm_path if perm_path.strip() != "" else "/"
+
             return perm_domain + perm_path
 
         # Skipped
diff --git a/src/yunohost/backup.py b/src/yunohost/backup.py
index 3e2f467d1..51aa7d6cd 100644
--- a/src/yunohost/backup.py
+++ b/src/yunohost/backup.py
@@ -872,7 +872,7 @@ class RestoreManager():
         Read the info file from inside an archive
 
         Exceptions:
-        backup_invalid_archive -- Raised if we can't read the info
+        backup_archive_cant_retrieve_info_json -- Raised if we can't read the info
         """
         # Retrieve backup info
         info_file = os.path.join(self.work_dir, "info.json")
@@ -885,7 +885,7 @@ class RestoreManager():
                 self.info["system"] = self.info["hooks"]
         except IOError:
             logger.debug("unable to load '%s'", info_file, exc_info=1)
-            raise YunohostError('backup_invalid_archive')
+            raise YunohostError('backup_archive_cant_retrieve_info_json', archive=self.archive_path)
         else:
             logger.debug("restoring from backup '%s' created on %s", self.name,
                          datetime.utcfromtimestamp(self.info['created_at']))
@@ -893,10 +893,6 @@ class RestoreManager():
     def _postinstall_if_needed(self):
         """
         Post install yunohost if needed
-
-        Exceptions:
-        backup_invalid_archive -- Raised if the current_host isn't in the
-        archive
         """
         # Check if YunoHost is installed
         if not os.path.isfile('/etc/yunohost/installed'):
@@ -908,7 +904,7 @@ class RestoreManager():
                 logger.debug("unable to retrieve current_host from the backup",
                              exc_info=1)
                 # FIXME include the current_host by default ?
-                raise YunohostError('backup_invalid_archive')
+                raise YunohostError("The main domain name cannot be retrieved from inside the archive, and is needed to perform the postinstall", raw_msg=True)
 
             logger.debug("executing the post-install...")
             tools_postinstall(domain, 'Yunohost', True)
@@ -1915,6 +1911,8 @@ class TarBackupMethod(BackupMethod):
 
         Exceptions:
         backup_archive_open_failed -- Raised if the archive can't be open
+        backup_archive_corrupted -- Raised if the archive appears corrupted
+        backup_archive_cant_retrieve_info_json -- If the info.json file can't be retrieved
         """
         super(TarBackupMethod, self).mount(restore_manager)
 
@@ -1926,6 +1924,11 @@ class TarBackupMethod(BackupMethod):
                          self._archive_file, exc_info=1)
             raise YunohostError('backup_archive_open_failed')
 
+        try:
+            files_in_archive = tar.getnames()
+        except IOError as e:
+            raise YunohostError("backup_archive_corrupted", archive=self._archive_file, error=str(e))
+
         # FIXME : Is this really useful to close the archive just to
         # reopen it right after this with the same options ...?
         tar.close()
@@ -1934,21 +1937,21 @@ class TarBackupMethod(BackupMethod):
         logger.debug(m18n.n("restore_extracting"))
         tar = tarfile.open(self._archive_file, "r:gz")
 
-        if "info.json" in tar.getnames():
+        if "info.json" in files_in_archive:
             leading_dot = ""
             tar.extract('info.json', path=self.work_dir)
-        elif "./info.json" in tar.getnames():
+        elif "./info.json" in files_in_archive:
             leading_dot = "./"
             tar.extract('./info.json', path=self.work_dir)
         else:
             logger.debug("unable to retrieve 'info.json' inside the archive",
                          exc_info=1)
             tar.close()
-            raise YunohostError('backup_invalid_archive')
+            raise YunohostError('backup_archive_cant_retrieve_info_json', archive=self._archive_file)
 
-        if "backup.csv" in tar.getnames():
+        if "backup.csv" in files_in_archive:
             tar.extract('backup.csv', path=self.work_dir)
-        elif "./backup.csv" in tar.getnames():
+        elif "./backup.csv" in files_in_archive:
             tar.extract('./backup.csv', path=self.work_dir)
         else:
             # Old backup archive have no backup.csv file
@@ -2290,7 +2293,7 @@ def backup_list(with_info=False, human_readable=False):
             try:
                 d[a] = backup_info(a, human_readable=human_readable)
             except YunohostError as e:
-                logger.warning('%s: %s' % (a, e.strerror))
+                logger.warning(str(e))
 
         result = d
 
@@ -2327,17 +2330,23 @@ def backup_info(name, with_details=False, human_readable=False):
     if not os.path.exists(info_file):
         tar = tarfile.open(archive_file, "r:gz")
         info_dir = info_file + '.d'
+
         try:
-            if "info.json" in tar.getnames():
+            files_in_archive = tar.getnames()
+        except IOError as e:
+            raise YunohostError("backup_archive_corrupted", archive=archive_file, error=str(e))
+
+        try:
+            if "info.json" in files_in_archive:
                 tar.extract('info.json', path=info_dir)
-            elif "./info.json" in tar.getnames():
+            elif "./info.json" in files_in_archive:
                 tar.extract('./info.json', path=info_dir)
             else:
                 raise KeyError
         except KeyError:
             logger.debug("unable to retrieve '%s' inside the archive",
                          info_file, exc_info=1)
-            raise YunohostError('backup_invalid_archive')
+            raise YunohostError('backup_archive_cant_retrieve_info_json', archive=archive_file)
         else:
             shutil.move(os.path.join(info_dir, 'info.json'), info_file)
         finally:
@@ -2350,7 +2359,7 @@ def backup_info(name, with_details=False, human_readable=False):
             info = json.load(f)
     except:
         logger.debug("unable to load '%s'", info_file, exc_info=1)
-        raise YunohostError('backup_invalid_archive')
+        raise YunohostError('backup_archive_cant_retrieve_info_json', archive=archive_file)
 
     # Retrieve backup size
     size = info.get('size', 0)
diff --git a/src/yunohost/domain.py b/src/yunohost/domain.py
index 65320feeb..82cbbc322 100644
--- a/src/yunohost/domain.py
+++ b/src/yunohost/domain.py
@@ -33,7 +33,7 @@ from yunohost.utils.error import YunohostError
 from moulinette.utils.log import getActionLogger
 
 from yunohost.app import app_ssowatconf
-from yunohost.regenconf import regen_conf
+from yunohost.regenconf import regen_conf, _force_clear_hashes, _process_regen_conf
 from yunohost.utils.network import get_public_ip
 from yunohost.log import is_unit_operation
 from yunohost.hook import hook_callback
@@ -124,6 +124,17 @@ def domain_add(operation_logger, domain, dyndns=False):
 
         # Don't regen these conf if we're still in postinstall
         if os.path.exists('/etc/yunohost/installed'):
+            # Sometime we have weird issues with the regenconf where some files
+            # appears as manually modified even though they weren't touched ...
+            # There are a few ideas why this happens (like backup/restore nginx
+            # conf ... which we shouldnt do ...). This in turns creates funky
+            # situation where the regenconf may refuse to re-create the conf
+            # (when re-creating a domain..)
+            # So here we force-clear the has out of the regenconf if it exists.
+            # This is a pretty ad hoc solution and only applied to nginx
+            # because it's one of the major service, but in the long term we
+            # should identify the root of this bug...
+            _force_clear_hashes(["/etc/nginx/conf.d/%s.conf" % domain])
             regen_conf(names=['nginx', 'metronome', 'dnsmasq', 'postfix', 'rspamd'])
             app_ssowatconf()
 
@@ -188,6 +199,25 @@ def domain_remove(operation_logger, domain, force=False):
 
     os.system('rm -rf /etc/yunohost/certs/%s' % domain)
 
+    # Sometime we have weird issues with the regenconf where some files
+    # appears as manually modified even though they weren't touched ...
+    # There are a few ideas why this happens (like backup/restore nginx
+    # conf ... which we shouldnt do ...). This in turns creates funky
+    # situation where the regenconf may refuse to re-create the conf
+    # (when re-creating a domain..)
+    #
+    # So here we force-clear the has out of the regenconf if it exists.
+    # This is a pretty ad hoc solution and only applied to nginx
+    # because it's one of the major service, but in the long term we
+    # should identify the root of this bug...
+    _force_clear_hashes(["/etc/nginx/conf.d/%s.conf" % domain])
+    # And in addition we even force-delete the file Otherwise, if the file was
+    # manually modified, it may not get removed by the regenconf which leads to
+    # catastrophic consequences of nginx breaking because it can't load the
+    # cert file which disappeared etc..
+    if os.path.exists("/etc/nginx/conf.d/%s.conf" % domain):
+        _process_regen_conf("/etc/nginx/conf.d/%s.conf" % domain, new_conf=None, save=True)
+
     regen_conf(names=['nginx', 'metronome', 'dnsmasq', 'postfix'])
     app_ssowatconf()
 
diff --git a/src/yunohost/regenconf.py b/src/yunohost/regenconf.py
index ad84c8164..4062628aa 100644
--- a/src/yunohost/regenconf.py
+++ b/src/yunohost/regenconf.py
@@ -473,6 +473,18 @@ def _update_conf_hashes(category, hashes):
     _save_regenconf_infos(categories)
 
 
+def _force_clear_hashes(paths):
+
+    categories = _get_regenconf_infos()
+    for path in paths:
+        for category in categories.keys():
+            if path in categories[category]['conffiles']:
+                logger.debug("force-clearing old conf hash for %s in category %s" % (path, category))
+                del categories[category]['conffiles'][path]
+
+    _save_regenconf_infos(categories)
+
+
 def _process_regen_conf(system_conf, new_conf=None, save=True):
     """Regenerate a given system configuration file
 
diff --git a/src/yunohost/tests/test_apps.py b/src/yunohost/tests/test_apps.py
index 6bc625a91..7c0861aa1 100644
--- a/src/yunohost/tests/test_apps.py
+++ b/src/yunohost/tests/test_apps.py
@@ -9,7 +9,7 @@ from conftest import message, raiseYunohostError
 from moulinette import m18n
 from moulinette.utils.filesystem import mkdir
 
-from yunohost.app import app_install, app_remove, app_ssowatconf, _is_installed, app_upgrade
+from yunohost.app import app_install, app_remove, app_ssowatconf, _is_installed, app_upgrade, app_map
 from yunohost.domain import _get_maindomain, domain_add, domain_remove, domain_list
 from yunohost.utils.error import YunohostError
 from yunohost.tests.test_permission import check_LDAP_db_integrity, check_permission_for_apps
@@ -142,6 +142,12 @@ def test_legacy_app_install_main_domain():
 
     install_legacy_app(main_domain, "/legacy")
 
+    app_map_ = app_map(raw=True)
+    assert main_domain in app_map_
+    assert '/legacy' in app_map_[main_domain]
+    assert 'id' in app_map_[main_domain]['/legacy']
+    assert app_map_[main_domain]['/legacy']['id'] == 'legacy_app'
+
     assert app_is_installed(main_domain, "legacy_app")
     assert app_is_exposed_on_http(main_domain, "/legacy", "This is a dummy app")
 
@@ -166,6 +172,12 @@ def test_legacy_app_install_secondary_domain_on_root(secondary_domain):
 
     install_legacy_app(secondary_domain, "/")
 
+    app_map_ = app_map(raw=True)
+    assert secondary_domain in app_map_
+    assert '/' in app_map_[secondary_domain]
+    assert 'id' in app_map_[secondary_domain]['/']
+    assert app_map_[secondary_domain]['/']['id'] == 'legacy_app'
+
     assert app_is_installed(secondary_domain, "legacy_app")
     assert app_is_exposed_on_http(secondary_domain, "/", "This is a dummy app")
 
diff --git a/src/yunohost/tests/test_backuprestore.py b/src/yunohost/tests/test_backuprestore.py
index bcba21bb6..c7a4f9016 100644
--- a/src/yunohost/tests/test_backuprestore.py
+++ b/src/yunohost/tests/test_backuprestore.py
@@ -574,9 +574,22 @@ def test_restore_archive_with_no_json(mocker):
 
     assert "badbackup" in backup_list()["archives"]
 
-    with raiseYunohostError(mocker, 'backup_invalid_archive'):
+    with raiseYunohostError(mocker, 'backup_archive_cant_retrieve_info_json'):
         backup_restore(name="badbackup", force=True)
 
+@pytest.mark.with_wordpress_archive_from_2p4
+def test_restore_archive_with_bad_archive(mocker):
+
+    # Break the archive
+    os.system("head -n 1000 /home/yunohost.backup/archives/backup_wordpress_from_2p4.tar.gz > /home/yunohost.backup/archives/backup_wordpress_from_2p4.tar.gz")
+
+    assert "backup_wordpress_from_2p4" in backup_list()["archives"]
+
+    with raiseYunohostError(mocker, 'backup_archive_open_failed'):
+        backup_restore(name="backup_wordpress_from_2p4", force=True)
+
+    clean_tmp_backup_directory()
+
 
 def test_backup_binds_are_readonly(mocker, monkeypatch):
 
diff --git a/src/yunohost/tests/test_regenconf.py b/src/yunohost/tests/test_regenconf.py
new file mode 100644
index 000000000..357f96c88
--- /dev/null
+++ b/src/yunohost/tests/test_regenconf.py
@@ -0,0 +1,80 @@
+import glob
+import os
+import pytest
+import shutil
+import requests
+
+from conftest import message, raiseYunohostError
+
+from moulinette import m18n
+from moulinette.utils.filesystem import mkdir
+
+from yunohost.domain import _get_maindomain, domain_add, domain_remove, domain_list
+from yunohost.utils.error import YunohostError
+from yunohost.regenconf import manually_modified_files, _get_conf_hashes, _force_clear_hashes
+
+TEST_DOMAIN = "secondarydomain.test"
+TEST_DOMAIN_NGINX_CONFIG = "/etc/nginx/conf.d/secondarydomain.test.conf"
+
+def setup_function(function):
+
+    _force_clear_hashes([TEST_DOMAIN_NGINX_CONFIG])
+    clean()
+
+def teardown_function(function):
+
+    clean()
+    _force_clear_hashes([TEST_DOMAIN_NGINX_CONFIG])
+
+def clean():
+
+    assert os.system("pgrep slapd >/dev/null") == 0
+    assert os.system("pgrep nginx >/dev/null") == 0
+
+    if TEST_DOMAIN in domain_list()["domains"]:
+        domain_remove(TEST_DOMAIN)
+        assert not os.path.exists(TEST_DOMAIN_NGINX_CONFIG)
+
+    os.system("rm -f %s" % TEST_DOMAIN_NGINX_CONFIG)
+
+    assert os.system("nginx -t 2>/dev/null") == 0
+
+    assert not os.path.exists(TEST_DOMAIN_NGINX_CONFIG)
+    assert TEST_DOMAIN_NGINX_CONFIG not in _get_conf_hashes("nginx")
+    assert TEST_DOMAIN_NGINX_CONFIG not in manually_modified_files()
+
+
+def test_add_domain():
+
+    domain_add(TEST_DOMAIN)
+
+    assert TEST_DOMAIN in domain_list()["domains"]
+
+    assert os.path.exists(TEST_DOMAIN_NGINX_CONFIG)
+
+    assert TEST_DOMAIN_NGINX_CONFIG in _get_conf_hashes("nginx")
+    assert TEST_DOMAIN_NGINX_CONFIG not in manually_modified_files()
+
+
+def test_add_and_edit_domain_conf():
+
+    domain_add(TEST_DOMAIN)
+
+    assert os.path.exists(TEST_DOMAIN_NGINX_CONFIG)
+    assert TEST_DOMAIN_NGINX_CONFIG in _get_conf_hashes("nginx")
+    assert TEST_DOMAIN_NGINX_CONFIG not in manually_modified_files()
+
+    os.system("echo ' ' >> %s" % TEST_DOMAIN_NGINX_CONFIG)
+
+    assert TEST_DOMAIN_NGINX_CONFIG in manually_modified_files()
+
+
+def test_add_domain_conf_already_exists():
+
+    os.system("echo ' ' >> %s" % TEST_DOMAIN_NGINX_CONFIG)
+
+    domain_add(TEST_DOMAIN)
+
+    assert os.path.exists(TEST_DOMAIN_NGINX_CONFIG)
+    assert TEST_DOMAIN_NGINX_CONFIG in _get_conf_hashes("nginx")
+    assert TEST_DOMAIN_NGINX_CONFIG not in manually_modified_files()