Connection to client fails - NOROUTE_DatabaseError

I try to connect to 2 different computers at a client site - but the connection fails with the followoing log-entries:

2018/08/08 15:49:01.831 1538 4529823744      S0     CProcessCommandHandlerMasterConnect[8]::ReceivedMasterResponse(): Received MasterCommand NOROUTE_DatabaseError
2018/08/08 15:49:01.832 1540 4509876224      D501!! SessionManagerDesktop::SessionTerminate: no session with ID=nnnnnnnnn
2018/08/08 15:49:01.832 1542 4555632640      G501!! LoginOutgoing: ConnectFinished - error: DatabaseError

I tried to connect multiple times for about a hour - from 3 different computers with 3 different Versions (11,12, and 13) on 2 different locations.

So, if it is no Problem at the client site (which I can't figure out now), it might be a problem on TeamViewers Servers?

Ciao

dirk