Hallo,
dies sollte eher ein Java-Problem sein.
Hier eine FAQ der JavaMailAPI:
Q: When connecting to my mail server over SSL I get an exception like "unable to find valid certification path to requested target". [updated!]
A: Your server is probably using a test certificate or self-signed certificate instead of a certificate signed by a commercial Certificate Authority. You'll need to install the server's certificate into your trust store. The InstallCert program will help.
Alternatively, you can set the "mail.protocol.ssl.trust" property to the host name of your mail server. See the javadocs for the protocol provider packages for details.
Other common causes of this problem are:
There's a firewall or anti-virus program intercepting your request.
There's something wrong in your JDK installation preventing it from finding the certificates for the trusted certificate authorities.
You're running in an application server that has overridden the JDK's list of trusted certificate authorities.
Bitte um Rückmeldung, ob dies zur Problemlösung führte