I’ve been trying for a few weeks now to add a new email mailbox.
The initial attempt proceeded beyond the selection of the email address, but the process did not complete.
Subsequent attempts to try again keep telling me that the email address is not valid. Mail tester.com say the email address is in use, but I presume it is from my first failed attempt. I have even tried to using variations on the email address which are shown as clear on mailtester.com, but the process keeps failing. I have tried the process on both laptop and iPad, but neither seems to work.
I see others have previously had similar problems.