The most popular BitTorrent client in the world was disabled for a sizable chunk of the Internet on Saturday night as hundreds of users took to Twitter and other social-media networks to complain about their uTorrent service. Some users found the client did work, but others mentioned browser crashes and files failing to download. The cause of the difficulty is not yet known.

In August, uTorrent had an international registered-user base of more than 125 million, according to TorrentFreak. Many of these users are fond of the BitTorrent client because it hosts thousands of music and movie files that are often obtained illegally. The site rose to prominence, though, because of its ability to skirt the distributed denial-of-service, or DDoS, attacks that have plagued other major players in the piracy game, such as The Pirate Bay and Demonoid.

Neither the official uTorrent Twitter feed nor the uTorrent Help feed had any explanation for the outage, as of this writing. Spanish-speaking Twitter users reported much of the technical difficulty, and there is confirmation that the site was working normally in the eastern regions of the U.S.

Some users went to the tech-support community boards on Reddit to ask for updates.

“Mac uTorrent won’t download. The torrent as about 140 seeds, 104 peers and a download speed of around 100kb/s. Yet, the torrent isn’t downloading,” wrote Redditor WilliamBlakeism, describing a file that would normally have no trouble downloading.  

There has been no confirmation about whether the downtime has been caused by a DDoS attack. However, another possibility could be a sudden influx of users trying to access uTorrent’s newest feature. This week, the BitTorrent client released an app for Android products with a Wi-Fi-only option, a popular move that’s seen as the next challenge copyright enforcers will have to face.

The Next Web reported the new app was designed with “fixed stability issues” and the removal of size and speed caps on mobile devices.