Configuring local email notifications fail with error message: General error occurred while sending mail - 454 4.7.0 TLS not available due to local problem.

Products

• VMware Usage Meter

Issue/Introduction

• To notify to a set of recipients about issues with VCF Usage Meter, you are configuring the local email notifications. After following the documented configuration steps, following error in encountered when clicking Save button even when Enable TLS/SSL check-box is not checked: General error occurred while sending mail - 454 4.7.0 TLS not available due to local problem.
• Following entries are recorded in vmware-um-journal.service-000.log:
  

  DATE hh:mm:ss UM-NAME start-journal-service.sh[1673]: yyyy-mm-ddThh:mm:ss ERROR 1673 --- [VCF Usage Meter Journal Service] [0.1-8051-exec-4] .s.n.v.MailNotificationSettingsValidator : Testing mail notifications fail. Used SMTP settings: SmtpSettings{smtpHost='<example.com>', smtpPort=25, smtpUser='null', smtpUseSsl=false}.
  DATE hh:mm:ss  UM-NAME start-journal-service.sh[1673]: jakarta.mail.MessagingException: 454 4.7.0 TLS not available due to local problem
  DATE hh:mm:ss  UM-NAME start-journal-service.sh[1673]:         at org.eclipse.angus.mail.smtp.SMTPTransport.issueCommand(SMTPTransport.java:####)
  DATE hh:mm:ss  UM-NAME start-journal-service.sh[1673]:         at org.eclipse.angus.mail.smtp.SMTPTransport.startTLS(SMTPTransport.java:####)
  DATE hh:mm:ss  UM-NAME start-journal-service.sh[1673]:         at org.eclipse.angus.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:###)
  DATE hh:mm:ss  UM-NAME start-journal-service.sh[1673]:         at jakarta.mail.Service.connect(Service.java:###)
  DATE hh:mm:ss  UM-NAME start-journal-service.sh[1673]:         at org.springframework.mail.javamail.JavaMailSenderImpl.connectTransport(JavaMailSenderImpl.java:###)

Environment

VCF Usage Meter 9.0.x

Cause

The SMTP server in use supports the STARTTLS extension. Consequently, the UM appliance attempts to initiate a secure connection via STARTTLS to upgrade the existing non-encrypted connection to a secure one. If this upgrade fails, the connection is terminated, resulting in the error observed.

Resolution

To resolve this issue import the certificate returned by the SMPT server into UM truststore. Here are the steps for the same:
1. The certificate being used can be viewed by executing following command:

openssl s_client -connect <smtp.server>:<port> -starttls smtp 

2. Copy the certificate returned by the SMTP server in a notepad and save the file in .cer format.
3. Import the certificate in Usage Meter appliance's truststore as per the instructions mentioned here.

Note: If no certificate is returned after running the above-mentioned command then disable the STARTTLS extension on your SMTP server. Once this is done, the issue should be resolved. 

Additional Information

StartTLS is an extension that instructs to upgrade existing non-SSL connection to secure one. It is not the same as 'Use TLS/SSL' on the UI.