Email replies to notifications won't send
If a user complains that they cannot reply to a Canvas notification from their email client without an error that the email could not send, it is usually because their email client is sending replies from permutation of their USU email address that isn’t in their Canvas account settings.
For example, many users have their first.last@usu.edu and a#@usu.edu addresses listed as “ways to contact” in their Canvas settings. But if their email client is using the a#@aggies.usu.edu version of their email address and putting that in the “from” line, Canvas won’t accept the reply to a notification they have received.
An easier solution than reconfiguring the user’s email client is for the user to also add their a#@aggies.usu.edu address to their “ways to contact” in their Canvas account settings.