Having a problem where the log-in simply doesn't work. A customer clicks 'Log In'; gets to the log in screen; enters email and pass and clicks 'Sign In', but is returned to the log in screen.
Where should I start to troubleshoot this issue?
Note: The issue occurs with any template.
(Zen Cart 1.3.7.1; PHP 5.2.4; MySQL 5.0.27-standard)



