When I do a 'import CA reply' I receive the error 'An error occurred importing the CSR reply. See server logs for details.

I have no clue which log to check. Checked catalina.out and several others. But can't find it....

The issue:
created a new key pair in the Web Application Certificates
created a csr
got my official certificate based on the csr
imported the trusted external root (Commodo) as a trusted certificate
imported the intermediate PositiveSSL CA 2 (Commodo) as a trusted certificate
import the crt as a reply for the key pair
Any clues?

Thanks in advance,