Chinese authorities have had it up to here with YouTube. It appears they’ve blocked the video service again.

Mashable says it’s because of a video “purportedly depicting Chinese security personnel beating Tibetans.” But the Chinese government claims the video is fake. The Economic Times, however, quotes a Dutch Internet entrepreneur who co-founded a Shanghai-based video-sharing site: “I suspect the real reason might be that YouTube just launched a Chinese version, which would make the site much more accessible for Chinese users,” wrote Marc van der Chijs.

Google, which owns YouTube, began noticing a decline in traffic from China about noon Monday. The “Network Timeout” error message continues today.

“We do not know the reason for the blockage and we are working as quickly as possible to restore access to our users,” said Scott Rubin, a spokesman for Google.