User forced logout on redirects

Hello, I noticed errors in the activity page where users were having trouble logging in. They seemed to log in correctly, but then received login failed errors immediately afterword. Testing myself in a new browser I was able to log in to a secondary account but was immediately logged out when trying to access a new page. Trying to sign up as a new user altogether was prevented as well (seemed to work but no confirmation email was sent and could not log in with new account). Any ideas? No other security plugins are installed, so no conflicts there.