diff --git a/conf/config.json b/conf/config.json
index 02a5719..8ddad7c 100644
--- a/conf/config.json
+++ b/conf/config.json
@@ -253,12 +253,12 @@
     "UseChannelInEmailNotifications": false,
     "RequireEmailVerification": false,
     "FeedbackName": "Mattermost notification",
-    "FeedbackEmail": "no-reply@__DOMAIN__",
+    "FeedbackEmail": "no-reply@__MAIN_DOMAIN__",
     "ReplyToAddress": "",
     "FeedbackOrganization": "",
     "EnableSMTPAuth": false,
-    "SMTPUsername": "mattermost",
-    "SMTPPassword": "__SMTP_USER_PWD__",
+    "SMTPUsername": "__APP__",
+    "SMTPPassword": "__MAIL_PWD__",
     "SMTPServer": "localhost",
     "SMTPPort": "25",
     "SMTPServerTimeout": 10,
diff --git a/manifest.toml b/manifest.toml
index 4a62848..465666e 100644
--- a/manifest.toml
+++ b/manifest.toml
@@ -87,6 +87,7 @@ ram.runtime = "50M"
         arm64.sha256 = "c75860817858eddde852075ec0c0091f53cec7858be30cc7f849f31e215bd23d"
 
     [resources.system_user]
+    allow_email = true
 
     [resources.install_dir]
 
diff --git a/scripts/_common.sh b/scripts/_common.sh
index 0d8f29f..58454f3 100644
--- a/scripts/_common.sh
+++ b/scripts/_common.sh
@@ -4,6 +4,11 @@
 # COMMON VARIABLES
 #=================================================
 
+# We want Mattermost emails to be sent from the main domain
+# (the one for which the emails headers are properly configured),
+# and not the subdomain or secondary domain used for Mattermost.
+main_domain=$(cat /etc/yunohost/current_host)
+
 #=================================================
 # PERSONAL HELPERS
 #=================================================