T-Zigbee zigbee2mqtt cannot connect to MQTT Server

[AT_]

Hello,

i got zigbee2mqtt and the missing filesystem uploaded onto the 2xT-Zigbees (platformio). I was able to connect to the AP and entered my Wifi and MQTT Server credentials.
While it connected with my wifi and is accessible via its wifi IP, it does not connect to my MQTT Server. In the serial message names and passwords are all correct, but the server name is nonsense. I tried just the IP adress, but also mqtt://IP, which does not parse (mqtt://mqtt://IP:1833), so i think just the IP should be correct. I have other devices connected with the MQTT-server.

Below the Serial messages:

name: ssid
args: ****
name: password
args: ****
name: server
args: ␜R�?␏
name: port
args: 1883
name: mqtt_username
args: *****
name: mqtt_password
args: *****
E (242988) MQTT_CLIENT: MQTT connect failed
E (247492) MQTT_CLIENT: MQTT connect failed
E (257508) MQTT_CLIENT: MQTT connect failed
E (258001) MQTT_CLIENT: MQTT connect failed
E (272519) MQTT_CLIENT: MQTT connect failed

Would be great if someone has some fix.
Thanks.