@michielp
Hello,
Maybe I can help.
I not sure what you used to make your Certs but the error might be from a couple issues.
Make sure the application has access to the Certs being used. The right certificates were inserted into the Keystore and the application has access to that keystore. The certs were configured incorrectly.
I have accually received this error before because I inserted the wrong certificate in the keystore.
As for troubleshooting further we need some more information.
If your unsure you can find more information here
Details you should always include
Hope that helps