Checking our email account it is showing Mail failure - malformed recipient address
The initial registration and email failure occurred when the board was running phpBB 3.3.5.Mail failure email wrote:A message that you sent contained one or more recipient addresses that were
incorrectly constructed:
=?US-ASCII?Q?P@n@m@?= <[email protected]>: malformed address: @m@?= <[email protected]> may not follow =?US-ASCII?Q?P@n
This address has been ignored. There were no other addresses in your
message, and so no attempt at delivery was possible.
------ This is a copy of your message, including all the headers. ------
To: =?US-ASCII?Q?P@n@m@?= <[email protected]>
The board was updated last night to 3.3.7 and through ACP I did a Force reactivation. The same failure email is received.
Is the username valid from phpBB's point of view? If so why does the mail system believe there is a malformed address?