Sending verification email fails with STARTTLS error, but works from Notifications Global Settings.

If I test an email from the Notifications Global Settings when the Mail Protocol is set to SMTP + STARTTLS, the test email is successfully received.

If I send a verification email from a User Preferences page for a user that is created in youtrack directly, the verification email is successfully received.

If I send a verification email from a User Preferences page for a user that is created by an LDAP Auth Module, the email fails to send and I get the following error:
 

If I go back to global settings and switch it to SMTP only (no STARTTLS), then the email is successful in all cases, but that is not an acceptable solution.

Is there anywhere I can find logs for this? I couldn't find any logs that would indicate what the issue is.