Good afternoon Daniel !
I too have this issue, using Desktop Microsoft Outlook, having never had a problem in all the years I've been a VM customer. I've managed to alter the settings to successfully receive emails using IMAP, rather than POP3, but I still have the issue when trying to SEND emails, even having updated the SMTP settings to the new "app" password. I did input the username as my "full" (eg xxxxxx@ntlworld.com) email address as per the article, so I'm thinking that might be the issue, but I'd welcome some help/guidance please.
Kind regards
Mike