If you sent out an email to your class through Blackboard, you may have received an email that had the subject "Undelivered Mail Returned to Sender." This message is telling you that it tried to send your email to all your students, and one or more of those student email addresses are incorrect. If you look into the body of the message, it will tell you what email addresses caused the problem.
If one of the email addresses causing the problem is update.email@WebAdvisor, that means one or more of your students doesn't have an email address in WebAdvisor.
You can find out which students are affected by going to the Control Panel, clicking on List/Modify Users, then click on the Search button to display all your students. Scan down the list to see who has update.email@WebAdvisor as their email address and give them a phone call.
Any changes made in Blackboard to the email address will be overwritten each night with the information in WebAdvisor, so students need to enter their correct email address in WebAdvisor. You can give students the link to these instructions on How to Your Change Email Address in WebAdvisor.
At the beginning of each semester, it might be a good idea to follow the steps above to scan through your student email addresses and make sure you have valid email addresses for each of them.