The error is stating that the system does not recognize me and is rejecting my order altogether.
So, it's not the Coupon that is not accepted, is the order itself ? In this case, there might be another problem with your Credit card or the address, but since we don't handle credit cards or ordering system, it's nothing we can control, for these issues, you have to contact Esellerate support at
support@esellerate.net
Give them the email you used to try the purchase, and they will surely explain what was wrong.