solved
I set Debuglevel to 2 an got following message:
So I think the problem is the certificate revocation check of Windows. Windows has no internet-Access in this Scenario, so the CA cannot be checked for revocations of the Cert.
. 2018-10-12 08:01:21.895 Certificate failed to verify against Windows certificate store: Error: 80092013, Chain index: 0, Element index: 0
So I think the problem is the certificate revocation check of Windows. Windows has no internet-Access in this Scenario, so the CA cannot be checked for revocations of the Cert.