Cannot force TLS in Messaging Gateway for mail delivery to Office 365

TECH251108

Last Updated August 08, 2018

Mail flow from the Symantec Messaging Gateway (SMG) to a Office 365 host has stopped
SMG has valid TLS certificates

454 Certificate Expired

TLS unable to complete the verification against Office 365 server because the Office 365 Certificate is expired/invalid/misconfigured.

Workaround

Temporarily change the protocol operation for the domain in question: Protocols > Domains > "UserDomain" > Delivery > RLS Encryption Section
Change the radio button to "Require TLS encryption and don't verify certificate"

Solution

Solution is to contact Microsoft for resolution of the certificate issue in the Office 365 configuration.

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