If you add or change the email alias that is shown on the “Alias” box on the Exchange General tab that is not the exact same as the “User logon name” in the Account tab , it can break POP3 and can also remove attributes in Active Directory/Exchange. Symptoms are loss of POP3 email and missing tabs in the user’s Active Directory account properties page on the Exchange server. The symptoms that we experienced were POP3 mail not working, Email Addresses tab completely missing, grayed out options and Delivery Options /Forwarding address issues.
After much research and troubleshooting the fix was to back up the entire mailbox, delete the mailbox and reconnect the Exchange mailbox. Here are the steps involved.
-Removed the alias that had been placed in the “Alias” section of the Exchange General tab in Active Directory Users and Computers on the Exchange server.
-EDSIedit did not want to work on connecting to the mailboxes that were affected to perform a backup of the email accounts, so we logged into user’s computer as the effected user and performed a full backup of the mailbox, contacts, calendar, etc from Outlook and saved as a PST to the local machine.
-After verifying the backup was successful, go to the Active Directory account from the Exchange server, and right click on account, Exchange Tasks then “Delete Mailbox”.
-Immediately go to Exchange System Manager, expand Admin Groups-First Admin Group-Servers-Your Server-Mailboxes and then Right click on the Mailboxes folder and select “Run Cleanup Agent”. This will make the deleted email account show up with a red x on it, otherwise you will have to wait.
-Right click on the email account that you deleted, and then select “Reconnect”, in the Active Directory dialogue box, enter the name of the primary Active Directory account for this email account, click “Check Name” to verify Exchange can access the account, then click finish. It should show the task as successful after the mailbox has been reattached to the domain user account.
-Once finished, go back to the User account in Active Directory on the Exchange server and all the tabs should be available again. You should verify all email addresses and aliases are listed in the Email Addresses tab and you very well may need to add aliases back to this tab. Also, verify any forwarders are setup and working and finally test POP3 email.