If you are attempting to reply to an instructors email and you are getting an error similar to this:

Delivery has failed to these recipients or groups:

Instructors name - instructor@concord.edu (do-not-reply@elearn.concord.edu)
Your message wasn't delivered. Despite repeated attempts to deliver your message, the recipient's email system refused to accept a connection from your email system.

The email you received originated at Blackboard, not from the instructors email address.  Notice the do-not-reply@elearn.concord.edu at the end of the email address, that is the ACTUAL email address it originated from, which is the Blackboard system.   Replying to it will fail.

To reach the instructor, start a NEW MESSAGE in your email and address it to the instructor's Concord email address, this is shown at the beginning of the email in the error, BEFORE the do-not-reply section.  Instructors' email addresses end with @concord.edu

If you still have issues you can contact the IT Helpdesk at 304-384-5291 or helpdesk@concord.edu