Seems like quite a few Mac users have this issue because they signed up with their Apple ID and used Hide My E-mail when they did so. Is that what you did?
There are numerous threads on this.
One reply from @colin that might apply:
Seems like quite a few Mac users have this issue because they signed up with their Apple ID and used Hide My E-mail when they did so. Is that what you did?
There are numerous threads on this.
One reply from @colin that might apply: