I just had this happen to me tonight. I re-entered the number 6 times, no luck. Tried later, wouldn't work. Then I realized I was trying to pay via the reminder email. I went to the original (1st) invoice sent and it worked! Hopefully this helps others. I have no idea if that was the fix but it worked for me.
Also, make sure the postal code has a space between *** ***.
I just had this happen to me tonight. I re-entered the number 6 times, no luck. Tried later, wouldn't work. Then I realized I was trying to pay via the reminder email. I went to the original (1st) invoice sent and it worked! Hopefully this helps others. I have no idea if that was the fix but it worked for me.
Also, make sure the postal code has a space between *** ***.