Do you get sun.security.provider.certpath. SunCertPathBuilderException: unable to find valid certification path to requested target when you try to send a mail from java via smtp(TLS and SSL)? There are 2 possible problems:

One option could be from the antivirus/firewall which prevent the communication for a specific port(default 465 for SSL and 587 for TSL) or for the java.exe. In the case you have a recent JDK/JRE and you use a well-known service this is probably the problem. Just try to disable the antivirus and to send again the mail from java. If it doesn’t work check the next point

You have an invalid/expired certificate for the email server so the SSL/TLS authentication doesn’t work properly. In order to overcome this you have to install the valid certificate.

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