Users posted screenshots on Twitter on Wednesday, showing that transfers of amounts like 6.40 yuan ($1) weren't going through. Instead, an error message popped up saying, "unusual transaction; please try again."
China's government censors have long snuffed out politically sensitive material -- for example, blocking search results or mentions of fallen leaders.
Using its "Great Firewall," Beijing routinely blocks Internet access to sites like Google, Facebook, Twitter and foreign media websites. Some people use virtual private networks, or VPNs, to get around the censors so they can check Gmail. But the government has been cracking down on that as well lately.