Same problem with me too...
I had the same problem. I think its on their side.
The thing is, if you get a problem once with a credit card, it will not work for any credit card after that.
So, when I changed it to my checking account, it went fine. Try that.
BTW, when I completed the E-file for the EAD renewal, it went to the MSC (Missouri Service Center). I was suprised. Is this how it works??