Why would a credit card not go through, if there is space on it?

Hubs is going to call the company tomorrow, but it's Thanksgiving today so they're closed lol so just curious if anyone's had this happen.

This is the second time a payment hasn't gone through when his card has plenty of space on it. A few months ago we got notice from our car insurance a payment didn't go through and now we got notice of the same from our house insurance. His card wasn't even close to its limit so it's really weird it didn't go through. Any ideas?