The popular fan fiction website Archive of Our Own (AO3) went offline Thursday, and its millions of users are freaking out.

The nonprofit behind AO3, the Organization for Transformative Works (OTW), initially announced Thursday that the website was down for maintenance.

But later updates revealed that the outage was more serious than routine maintenance. OTW warned that restoring the website could take at least two weeks and possibly up to four weeks.

“During that time, we may be able to bring the site back up in a degraded state, meaning that not all features will be available and/or the site may be read-only,” the update reads .…