Can't buy RP.

Trying to buy RP, it just keeps saying "You have encountered an error. Please try again later.". I tried resetting my IE config and security settings down to medium, followed by restarting the client, but that didn't do anything. I'd really appreciate some help on this. Thanks in advance!

Edit: I've bought a lot of RP today, and nothing has changed since then, so I don't know what's up.

Edit 2: Just checked my card on Steam, works fine.