diff --git a/src/yunohost/app.py b/src/yunohost/app.py
index 360f31abc..282f37c72 100644
--- a/src/yunohost/app.py
+++ b/src/yunohost/app.py
@@ -2624,7 +2624,7 @@ def _validate_and_normalize_webpath(manifest, args_dict, app_folder):
            and re.search(r"(ynh_webpath_register|yunohost app checkurl)", install_script_content):
 
             domain = domain_args[0][1]
-            _assert_no_conflicting_apps(domain, "/")
+            _assert_no_conflicting_apps(domain, "/", full_domain=True)
 
 
 def _make_environment_dict(args_dict, prefix="APP_ARG_"):
diff --git a/src/yunohost/domain.py b/src/yunohost/domain.py
index b3ef1299e..8a9917864 100644
--- a/src/yunohost/domain.py
+++ b/src/yunohost/domain.py
@@ -388,7 +388,8 @@ def _get_conflicting_apps(domain, path, ignore_app=None):
 
     return conflicts
 
-def _assert_no_conflicting_apps(domain, path, ignore_app=None):
+
+def _assert_no_conflicting_apps(domain, path, ignore_app=None, full_domain=False):
 
     conflicts = _get_conflicting_apps(domain, path, ignore_app)
 
@@ -402,7 +403,10 @@ def _assert_no_conflicting_apps(domain, path, ignore_app=None):
                 app_label=app_label,
             ))
 
-        raise YunohostError('app_location_unavailable', apps="\n".join(apps))
+        if full_domain:
+            raise YunohostError('app_full_domain_unavailable', domain=domain)
+        else:
+            raise YunohostError('app_location_unavailable', apps="\n".join(apps))
 
 
 def domain_url_available(domain, path):