Scan to email using Exchange email server

I have 3 Xerox WorkCentres (5855, 5755, 5875) in one location. I'm trying to set up Scan to Email on each of them. I'm on my second WC after successfully testing the first one. After setting it up exactly like the first one it will not work. I get a message "server address is not available" when I test the scan to email.

I double-checked all the settings I can think of.

Any suggestions?