Suddenly every user cannot log in to Cattr web app and desktop app. This was working fine for more than a month but now for everyone who tries to login (even the admin), it says 'We can't find the user with the provided credentials. No one has reset the password and we are not sure why this is happening. The domain to the login page is working fine so this is not a configuration issue.

Can anyone guide us towards a solution?
Did you changed domain name recently? What do you see at the users table of the database?