Try a delay

src/freedombone-app-xmpp

@@ -677,6 +677,8 @@ function install_xmpp_main {
 
     systemctl restart prosody
 
+    sleep 5
+
     prosodyctl register $MY_USERNAME $DEFAULT_DOMAIN_NAME "$XMPP_PASSWORD"
     if [ ! "$?" = "0" ]; then
         echo ''