At this moment, our only hosting provider has been unresponsive for two hours (the main and secondary sites are down, support is silent, and other server owners on this hosting provider are experiencing the same issue).
We hope that everything will be resolved within the next six hours, but right now we're simultaneously transitioning to a new hosting provider, which will temporarily serve as our primary server and later as a backup server in case of similar emergencies (if the primary one is restored).
Thankfully, after the previous incident (the hosting provider's disk burned out, containing all the server data), we have automated backups that will help us restore everything except the last eight hours.
It's unclear exactly how long the transition will take. Most likely, a day.
Technical issues
Source: Steam Community (opens in a new tab)