Updated: The issue has now been resolved!
Outdated:
We are receiving reports that some players are always receiving a "server error" message when attempting to purchase Gold via the Steam Wallet. We are currently investigating the causes of this problem and are working to resolve the situation as quickly as possible.
You can come back to this article later to see if the issue has been resolved.
Resolved! July 18th: Some players are unable to buy Gold via Steam
