Credit card blocks

[PokerEveryDay]

What exactly is blocking the transactions for credit cards online? I knew a long time ago that most credit cards don't work. Today was the day I decided to dig into this issue.

Stars states it could be because of the internet gaming restrictions. No one at my credit card company has a clue. There are no blocks on my card that they know of. They claim there isn't any middle man between them and any merchant. So what is blocking the transactions?