We have used "recent mode" for POP3 email* ever since VM switched to Gmail (in 2009?). It survived the switch back in-house in 2015. But it seems now to have stopped working. Is this the result of a change in VM's servers? Unannounced?
a. by "recent mode" I mean prefixing the user name (for Logon only) by "recent:"
b.it now produces an "Authentication failed" error
*It allows email from the account to be downloaded to more than one device.
The pop3 service has suddenly stopped working for me. So I can't fetch mail and read it in my preferred editor on my computer: have to login and read mail using the VM browser interface, which I have always hated, and still hate. Moreover I was not sent any warning that the system was going to change. Does VM want to drive away its long term users by messing them around without any warning or explanation of what's chaniging?
Have you changed all server settings (so for IMAP, POP, SMTP) from Blueyonder (or other legacy domain name) to Virginmedia ? When you do that on a number of clients you'll find that the password needs re-entering. So my main email address is <oldgoat> @blueyonder.co.uk, that's working just fine, but my client settings needed changing to pop3.virginmedia.com and smtp.virginmedia.com, and then I had to reenter my password.
From my previous Blueyonder settings the security and port numbers didn't change, can't say if that applies universally.