Hum I’m not sure what that would be. Are you on computer or phone? Have you tried to log in on a different device and get the same thing?
Can you try to use a different device and see if you’re still getting logged out? Try a phone and computer if you can. I haven’t had this reported from anyone else, so I’m trying to isolate the problem by ruling out if it’s a Mobil device issue, or an account issue.
Can you remember making any changes to your account recently? Like turning on notifications for a thread, or following a member or anything?