BO 4.3 Fiori Launchpad - Logon failed for RESTful Web Services

Hello,

iam running a fresh Installation of BO 4.3 and get always the following Error if i try to Login into the new Fiori Launchpad:

Logon failed for RESTful Web Services

If iam running the following URL (http://server-fqdn:8080/biprws/v1/logon/token) iam getting the following Error:

<error><error_code>RWS 00070</error_code><message>Internal server error. (RWS 00070)</message></error>

The Admin Cockpit in the CMC is running without any Errors. I've editet the Restful URL already to Port 8080.

Iam running out of ideas what the reason for the error could be.