Are you able to check if you receive the mails when not connected to our WiFi?
I'm sorry Alex, that makes no sense (to me). My only view of my email folders is as they are stored on your IMAP servers. Whether I view those via your webmail or via my email (IMAP) client they must look the same. How can wifi make a difference?
To re-phrase my problem, messages from a mailing list that I have been receiving in my inbox for years have suddenly started to appear in my Spam folder instead. The issue appears to me to be entirely down to a change made in your email service that is now categorising these emails as Spam.
This change happened around the 27th/28th January.
I understand that you don't actually run your own email service any more and will need to hand this over to them to diagnose further.
Thanks in advance,
Steve Platt