Hello Pider
thanks for your reply.
Yes I know that the missing Cert is the problem, but why is LetsEncrypt not creating it???
I could access the UMC again after following the instructions here: Web console not responding after letsencrypt upgrade fail
But when ever I run LetsEnrypt again I got other problems. Therefore I reinstalled the UMC Server again, it was not yet in production. Now it works, I just lost a few hours that’s all.
thanks anyway