Casio s400 e35 - Casio Parts Cash Register PC Desktop

Change amount exceeds preset limit.
Someone has programmed a limit on payments (usually on the cash button). Try paying by a different method (check, credit) and see if it opens the drawer. If so, you will need to re-program the cash button for no change limit. There is a code to do this in your manual. I don't have any info for programming this model. If you don't have a manual, one of the users has the SE-S400 Casio manual here:
http://the-checkout-tech.com/manuals/cashregisters/Casio_SE-S400_Operation_and_Programming_manual.html