Email configuration issue

Thu Sep 07 23:40:20 CST 2017
org.apache.commons.mail.EmailException: Sending the email to the following server failed : smtp.mail.yahoo.com:465
at org.apache.commons.mail.Email.sendMimeMessage(Email.java:1421)
at org.apache.commons.mail.Email.send(Email.java:1448)
at com.kms.katalon.execution.util.MailUtil.sendSummaryMail(MailUtil.java:129)
at com.kms.katalon.execution.launcher.ReportableLauncher.sendReportEmail(ReportableLauncher.java:157)
at com.kms.katalon.execution.launcher.ReportableLauncher.sendReport(ReportableLauncher.java:123)
at com.kms.katalon.execution.launcher.ReportableLauncher.preExecutionComplete(ReportableLauncher.java:80)
at com.kms.katalon.execution.launcher.ProcessLauncher.onWatchdogComplete(ProcessLauncher.java:171)
at com.kms.katalon.execution.launcher.LaunchWatchdog.notifyProcessTerminated(LaunchWatchdog.java:135)
at com.kms.katalon.execution.launcher.LaunchWatchdog.run(LaunchWatchdog.java:65)
at java.lang.Thread.run(Thread.java:745)
Caused by: javax.mail.MessagingException: Exception reading response;
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.readServerResponse(SMTPTransport.java:1462)
at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1260)
at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:370)
at javax.mail.Service.connect(Service.java:297)
at javax.mail.Service.connect(Service.java:156)
at javax.mail.Service.connect(Service.java:105)
at javax.mail.Transport.send0(Transport.java:168)
at javax.mail.Transport.send(Transport.java:98)
at org.apache.commons.mail.Email.sendMimeMessage(Email.java:1411)
… 9 more
Caused by: 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 sun.security.ssl.Alerts.getSSLException(Alerts.java:192)
at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1949)
at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:302)
at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:296)
at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1509)
at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:216)
at sun.security.ssl.Handshaker.processLoop(Handshaker.java:979)
at sun.security.ssl.Handshaker.process_record(Handshaker.java:914)
at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1062)
at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1375)
at sun.security.ssl.SSLSocketImpl.readDataRecord(SSLSocketImpl.java:928)
at sun.security.ssl.AppInputStream.read(AppInputStream.java:105)
at com.sun.mail.util.TraceInputStream.read(TraceInputStream.java:97)
at java.io.BufferedInputStream.fill(BufferedInputStream.java:246)
at java.io.BufferedInputStream.read(BufferedInputStream.java:265)
at com.sun.mail.util.LineInputStream.readLine(LineInputStream.java:75)
at com.sun.mail.smtp.SMTPTransport.readServerResponse(SMTPTransport.java:1440)
… 17 more
Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:387)
at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:292)
at sun.security.validator.Validator.validate(Validator.java:260)
at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:324)
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:229)
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:124)
at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1491)
… 29 more
Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at sun.security.provider.certpath.SunCertPathBuilder.build(SunCertPathBuilder.java:141)
at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:126)
at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:280)
at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:382)
… 35 more