Web gui not accessible - Firewall ist starting - Sophos XG - Tomcat Server DEAD can't be restarted

Sohos XG 18.0.5 MR-5-Build 586

Hi,

I'm not able to connect to my Sophos XG via web gui and SSH.
The web gui states 'Firewall is starting' all the time. SSH states 'remote side unexpectedly closed network connection'.

I followed the steps in this KB: https://support.sophos.com/support/s/article/KB-000038694?language=en_US#Check-and-restart-service-status

But it's not possible to restart or start the service at all. It always gives '503 Service Failed'.
How can I fix this without restarting the XG?

kind regards

Dirk