I don't know if this is an error, a license, or a system problem.
Do you use Office365 as your mail provider, MS have stopped IMAP Basic Authentication see Basic Authentication Deprecation in Exchange Online – September 2022 Update Your Office365 Admins should be aware.
You will need to move to using OAUTH which on the modern release of Web Help Desk support. I see your support has expired so you should install an update WHD license if an upgrade is required.
