What does code 00 or 85 mean?

00 or 85 on your Point of Sale device is general code that a point of sale can display

Error code 00:

If you encounter an error code 00, it means that the credit card processing network or the customer's issuing credit card bank has generated a 00 approval or decline response code. We recommend double checking the customers information. If this error happens again you may need to contact your payment processor.

Error code 85:

If you receive an error code 85, this is an older code and similar to error code 00, it could indicate that the issuer system is temporarily unavailable. We recommend that you double check the customers information and try again.