Cannot create new orders

[hontoir]

I have just updated to Prestashop 1.6 and updated my theme accordingly.

 

This issue is happening with the default theme and new theme.

 

Guest check out is disabled.

 

If I sign in to my previous 'test customer' account, an error message is created and I am not able to proceed with the order.

 

If I try to create a new customer then clicking the save button automatically updates the database and in the back office it adds the new customer, but nothing happens on the front end. It does not seem to move onto Step 2 (Delivery Options) 

 

Any assistance is appreciated

 

Mike

Edited May 6, 2016 by hontoir (see edit history)