Troubleshooting "451 4.4.62 Mail Sent to the Wrong Office 365 Region" Error on SMG

Products

• Messaging Gateway

Issue/Introduction

If you're seeing the error "451 4.4.62 Mail sent to the wrong Office 365 region. ATTR35 [No TLS]" on your Symantec Messaging Gateway (SMG), it means that Office 365 is rejecting the email, not SMG. This occurs when emails are sent to the wrong Office 365 region or when TLS encryption is missing.

Cause

• Region Mismatch: Office 365 has multiple geographic regions. If the email is sent to the wrong region, it will be rejected.

• No TLS: If the email isn't encrypted with TLS, Office 365 might block it.

 

Resolution

• Check SMG Settings: Ensure that SMG is correctly routing emails to the right Office 365 region and that TLS is enabled for outgoing mail.

• Contact Office 365 Support: Reach out to Microsoft to confirm the correct region and to verify any TLS requirements.