You receive the below error when emailing a TechMail address through Gmail, where john.doe@ttu.edu is the email address to which you sent a message:

Message blocked

Your message to john.doe@ttu.edu has been blocked. See technical details below for more information.

The response from the remote server was:

550 5.4.1 Recipient address rejected: Access denied.

The TechMail address was misspelled or is not active.

Double-check the spelling of the email address in the "To" field and verify that it is an active TechMail address.

Outcome

You can send the message without receiving a non-delivery notification.