diff --git a/src/freedombone-app-xmpp b/src/freedombone-app-xmpp
index 1ca05029..9cf78788 100755
--- a/src/freedombone-app-xmpp
+++ b/src/freedombone-app-xmpp
@@ -375,7 +375,10 @@ function update_prosody_modules {
 
 function upgrade_xmpp {
     if [ -d /etc/letsencrypt ]; then
-        usermod -a -G ssl-cert prosody
+        prosody_groups=$(groups prosody)
+        if [[ "$prosody_groups" != *'ssl-cert'* ]]; then
+            usermod -a -G ssl-cert prosody
+        fi
     fi
     function_check update_prosody_modules
     update_prosody_modules