Terraform Enterprise SMTP settings "Delivery Test Error" has no details

Problem

When entering SMTP settings in TFE, failures in test deliveries do not give enough detail to troubleshoot. The only error shown is  

Error saving SMTP settings Delivery Test Error

Cause

• If there is any failure in connecting to or sending via the specified SMTP server, the only error shown to the screen is not actionable.

Solutions:

• To get a more descriptive error you'll need SSH access to the TFE server
• Run this command:
  • For Terraform Enterprise versions or or after v202205-1:
    

    • docker logs tfe-atlas | grep 'SMTP'

  • For older versions of Terraform Enterprise:

    • docker logs ptfe_sidekiq | grep 'SMTP'

Outcome

The 'docker logs' command above should give more details on the problem and how to resolve. If you require assistance with the error found by the command, please open a ticket with Hashicorp Support.