System is throwing below exception when doing test connectivity .

A secure connection could not be established with the outgoing(SMTP) email server. Check the application server configuration.

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

  at com.sun.mail.smtp.SMTPTransport.startTLS(SMTPTransport.java:1999)

  at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:709)

  at javax.mail.Service.connect(Service.java:364)

  at javax.mail.Service.connect(Service.java:245)

  at com.pegarules.generated.SendEmailMessage_071021_cVrAdU43RqSkB9eOfCvqOw.SendEmailMessage07_10_21(SendEmailMessage_071021_cVrAdU43RqSkB9eOfCvqOw.java:354)

  at com.pegarules.generated.SendEmailMessage_071021_cVrAdU43RqSkB9eOfCvqOw.invoke(SendEmailMessage_071021_cVrAdU43RqSkB9eOfCvqOw.java:88)

  at com.pega.pegarules.generation.internal.library.LibraryRuntime.resolveAndinvokeFunctionViaReflection(LibraryRuntime.java:133)

  at com.pega.pegarules.generation.internal.library.LibraryRuntime.invokeLibraryRuntime(LibraryRuntime.java:110)

  at com.pega.pegarules.session.internal.mgmt.Executable.invokeLibraryRuntime(Executable.java:9017)

  at com.pega.pegarules.priv.generator.LibrarySupport.resolveAndInvokeFunctionViaReflection(LibrarySupport.java:181)

  at com.pegarules.generated.pega_integrationengine_default.SendEmailMessage(pega_integrationengine_default.java:197)

  at com.pegarules.generated.activity.ra_action_smtpconnectivity_259e7ea4a68eafe01cbff512df43e014.step8_circum0(ra_action_smtpconnectivity_259e7ea4a68eafe01cbff512df43e014.java:871)

  at com.pegarules.generated.activity.ra_action_smtpconnectivity_259e7ea4a68eafe01cbff512df43e014.perform(ra_action_smtpconnectivity_259e7ea4a68eafe01cbff512df43e014.java:222)

  at com.pega.pegarules.session.internal.mgmt.Executable.doActivity(Executable.java:3510)

  at com.pega.pegarules.session.internal.mgmt.Executable.invokeActivity(Executable.java:10587)

  at com.pegarules.generated.activity.ra_action_pysmtpconnectivity_9faffc8543aa6d41992fccc02fee5c94.step2_circum0(ra_action_pysmtpconnectivity_9faffc8543aa6d41992fccc02fee5c94.java:282)

  at com.pegarules.generated.activity.ra_action_pysmtpconnectivity_9faffc8543aa6d41992fccc02fee5c94.perform(ra_action_pysmtpconnectivity_9faffc8543aa6d41992fccc02fee5c94.java:86)

  at com.pega.pegarules.session.internal.mgmt.Executable.doActivity(Executable.java:3510)

  at com.pega.pegarules.exec.internal.declare.infengine.pages.DeclarativePageDirectoryImpl.runRule(DeclarativePageDirectoryImpl.java:1010)

  at com.pega.pegarules.exec.internal.declare.infengine.pages.DeclarativePageDirectoryImpl

After gone through the couple of PDN articles ,i got to know that problem with TLS,so as suggested in article,disable TLS by creating below DSS.

   DSS Name:   Email/DisableSecuritySTARTTLS
   Applies to:     Pega-IntSvcs
   Value:            true

Now, test connectivity of email server is successfully, but still outbound email is not getting triggered , and got the below error in tracer .

** Caught com.sun.mail.smtp.SMTPSendFailedException: 530 5.7.0 Must issue a STARTTLS command first. 88sm58169759pfj.20 - gsmtp

Note: it worked perfectly when application was running on 7.1.9 version, got the issue after migrated to 7.2.

PRPC : 7.2 V