Mysterious Login and Forgotten Password issue

[dieslepo]

While testing shipping modules I discovered returning customers could not login.

 

There are no problems signing up and making purchases, but after logging off, it is impossible to log back in. The login.php page just keeps refreshing on submit. Also, the 'forgotten password' page just loops on 'submit' and won't do anything.

 

Checked the database and all users present.

Tried forcing cookies. No difference

Checked both config.php files and seem to be no issues there.

 

What could be causing this and what info do you need to help!?

 

Thanks in advance