changing payment information

[yourehoneybee]

I need to change my payment information to my new debit card but every time I try to update it I get a red error message telling me to enter my expiry month. Clearly, I've already entered the expiration of my card into the appropriate box. I've tried it 1220 & 12/20 (as asked for in the example) & it won't accept it either way. Please help.