listserv mail

I have subscribed to a listserv for many years. The mail is sent to the list members from [email protected]

About 10 days ago, the mail from the server stopped arriving. It is either being deleted automatically  or ends up in webmail Junk folder. If I try to move it from 'Junk' to the Inbox, or mark it 'Not Spam', it simply gets deleted. Why are Telus' servers deleting my mail?