I have a problem connecting to a SMTP Server with Apache Commons Mail. I have tried everything but the only thing I can find online is for Java Mail. This is my error:
Caused by: javax.mail.MessagingException: Could not convert socket to TLS; nested exception is: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
I have seen that you can fix the issue on Java Mail with props.put("mail.smtp.ssl.trust", "smtp.gmail.com"); for example, but I can't a equivalent command to use on Apache Commons.
If you're really connecting to Gmail, you shouldn't need that. The Gmail certificate will be trusted by the default trust store. If you've configured a non-default trust store, add the Gmail certificate to that trust store using the InstallCert program.