I can still access my Tiscali emails through desktop browser. They have stopped working on both iPad and iPhone a week ago.This has happened quite a few times over last years and usually rights itself after a few days. When I have in the past been able to speak to someone at support they have asked me to delete the account and then add. I tried this on the iPad but I keep getting message “the password for IMAP .talktalk.net is incorrect “. I’ve changed talk talk password and it still doesn’t work. I went onto Apple support for 2.5 hours and they said they’d never seen anything like it, tried for ages to sort but couldn’t. Said I need to speak to you.
Are you a TalkTalk Consumer (home broadband) customer? If so, have you added the talktalk mailboxes to your MyAccount? That's essential to make sure you can access mail messages on all your email apps.