If your mobile phone stops reading your email, the easiest way to solve it is to delete the email account on your mobile phone and then add it again according to the guide in the link list below.
If you use an email client other than Outlook, e.g. Thunderbird and connects via IMAP, we primarily recommend that you switch to Outlook or webmail. If you want to continue using one of the other email clients, you need to change the settings so that it uses Oauth2 instead of Basic Authentication. See IMAP settings in the link list below for what settings your email client that connects via IMAP needs to have in order to continue reading e-mail from LTU.