[*Edited with corrected information. Solution included]
The same thing happened to me today, but worse -- the aliases don't seem to work. (the aliases still work, forwarding was delayed when I had initially tested the old aliases). And I get error messages that prevent me from adding back any aliases. I am currently on the phone with tech "support", and they the first level of tech support personnel have no ability to fix anything -- i.e., all of my aliases are lost.
If your aliases are important, I advise creating a back-up of the list of aliases, and periodically checking if they work.
Personally, I am moving to a different email hosting provider immediately!
UPDATE:
After another hour on the phone, in which the "back end" tech support department finally became involved, I was given a work-around, which may be helpful to others experiencing vanished aliases:
- Log in at outlook.office.com/ecp/ (or log in to your email account and then navigate to this link -- it will use your email login credentials).
- Click "recipients" in the left-hand navigation menu.
- Select the "mailboxes" tab in the middle panel.
- Select the email account from the displayed list, then click the Pencil ("Edit") icon.
- Select "email address" in the left-hand navigation menu within the edit window; you should now see a list of your aliases.
- To add a new alias, click the "+" icon, and select "SMTP", then add the alias address (including the domain name) in the "Email address" field, and click OK.
