When adding email notifications to the Resource Monitoring Tool, a TLS error will show even though SSL is not enabled

Issue

When setting up notifications on the Resource Monitoring Tool, when using plain text (no SSL) an error will occur when testing settings that a TLS certificate could not be verified.

Environment

Tableau Resource Monitoring Tool 2020.2.2
Windows Server

Resolution

Workaround

Use SSL when sending to the email server. If there are errors, investigate the errors and resolve the issues with certificate chain permissions.
Change the email server to be unencrypted, rather than TLS Optional

Cause

In some cases, when a mail server is set to TLS Optional, attempting to use the server without SSL will fail sending email from the remote monitoring tool. This issue is under investigation by development team.

Additional Information

Unlike Tableau Server, the Resource Monitoring Tool uses the Windows certificate manager rather than a Java keystore. This may cause some different SSL certs to appear unverified if they are not in the Windows keystore. This can result in an email server working with the same cert in Tableau Server but not with the Resource Monitoring Tool.