It is working now, but there is a big delay between things being posted on Kbin.social and then showing up here. I am pretty sure this is because Kbin.social is struggling with so many users.
The same is true with lemmy.ml. Posts from there are also delayed.
It's getting better. @[email protected] recently changed a setting in the nginx_internal.conf on lemmy.wtf (suggested herer) and we are now able to subscribe in both direction, I think.
Not all older posts/comments are automatically federated, but you can manually "pull" them over by searching for the full source URL on the destination instance. Which I do from time to time.
In order to catch up with a massive queue backlog a temporary hold on delivery to domains that are being problematic has been setup. Those other domains aren’t responding to kbin.social’s requests properly and so our own queues are getting backed up.
It’ll all be back to normal soon. Once the queues are sensible we can reenable domains as they start becoming responsive to us.