I can no longer access CRM "You must specify a valid username and password"

When I tried to login today, the system tells me “You must specify a valid username and password.” but I entered the correct details. It also doesnt let me retrieve my password because it doesnt recognize my email/Username combination.

You must look for the cause by inpecting your logs.

Also check if you have enough disk space, when disk space runs out the session manager can’t create a file and you can’t login.