There was a bug with KBin some days ago where it would send huge amounts of federation activities to Lemmy instances which would overload them. To mitigate this, lemmy.world and some other instances had to block kbin.social. I believe the .world admins tried to get in contact with @ernest. You can read some more details here.
I would also suggest that you and Ernest join the Lemmy Admin chat on Matrix where this problem was found and discussed.