Kickass Torrents, which recently became the world’s most popular torrent site, is down today. The site is simply not loading, resulting in generic errors like “This webpage is not available” in Chrome and “The connection has timed out” in Firefox.

It’s not currently clear what the problem is. This could be a software or hardware issue, but it’s also possible that, given the nature of the Kickass Torrents website, an anti-piracy group has had the site taken down. Kickass Torrents has a history of problems with copyright holders, and has been forced to switch domains in the past.

The Kickass Torrents is currently hosted at kat.cr, a domain name from Costa Rica. The .CR registry does not screen the content of its domains proactively, which is one of the reasons the torrent site switched to it. That said, the registry can revoke domain names under certain conditions, including when it receives a court order.

Following The Pirate Bay’s worst outage, at the end of 2014, and then a slew of hiccups every few months in 2015, Kickass Torrents has become the biggest alternative site for torrent users. Although it had other problems, the site was significantly more reliable.

And yet, today KAT is down without any explanation. Naturally, it’s impossible to reach anyone through the site’s blog (Google cache shows it was updated just a few weeks ago to wish its users “Merry Xmas”). There are also no updates from the official Twitter account.

We have contacted Kickass Torrents for more information and will keep you posted if we learn more about the outage, as well as if, and when, the site comes back.

Update at 11:00 a.m. Pacific: And just like that, KAT is back.