A couple of years ago, I set up a dial up account for my father in law which he has used very infrequently. He has, as for as I know never used plusnet's emails and consequently can't remember any password for web mail. He can log in to his plus net account, but can't log in to web mail. On myaccount the passwords are the same, I would have thought they would be for him too, but it's coming up with an "unknown user or password" message. Any suggestions as to what are can do to get web-mail working?
The passwords for the defaulr mailbox in webmail and the plusnet account should be the same. If this is a dialup account not used for ages it may have been removed (or partially removed) in Plusnets purge of inactive dialup accounts I suggest you login to the account and raise a ticket asking what the status of it is. If PN say it is intact, try changing the password on the portal, wait an hour and try webmail again. Or try the password change first and if it dpes not work raise a ticket.