I rarely wake up during the night but last night I did and had a couple of emails about a couple of Mastodon instances having trouble federating.
This was at 5am and after 14 hours (it's now 7pm) I found a solution to the problem, just removing 2 's' from the Mastodon code: https://github.com/tootsuite/mastodon/pull/12812 
@kraehenpost there is possibility that I'm still sleeping and this is some weird dream :)
@hugo This problem has been noticed by some server administrators and looking for a solution. Thanks for your contribution!
@noellabo It's possible that all instances running in Docker are affected by this.
@hugo that's usually how the most frustrating problems end out 😜
@lazar But obviously I was wrong :) I just worked around the issue, not solved it. Going back to debug this today
@hugo have fun!
@hugo Hero! 👍🙏