One thing that seems to be consistent across the entire fediverse is that it is incredibly unstable. Most of the admins running a lot of them are not professional cloud engineers and are still learning how to do HA (high availability) for scale. This is doubly complicated by Lemmy itself not being well engineered for that kind of configuration and that building systems that way exchanges stability for raw dollarydoos and every Lemmy server is self funded.

Check here. Tl;Dr is that they were under attack again (probably Hexbear tankies if I had to guess), and taking the comment section offline is helping them stay up.