Talk:Shop/Purchasing/@comment-26519286-20150831221845/@comment-26091666-20150901001104

Check with your financial institution provider to see if they rejected any transactions during a certain time period (needless to say, when you started enrolling your credit card to DMM site till like probably now).

It could be that either you or your financial institution prevented some transaction and hence DMM (temporarily) stopped accepting that credit card info.