I have broken kepi’s ActivityPub implementation somehow. At least, Mastodon isn’t loading user pages any more. I can’t see anything I changed that would make such a difference.
See e.g. https://marnanel.org/users/marnanel .
The preceding webfinger lookup works fine. The MIME types in Accept and Content-Type appear fine. Some of the Collections linked from that Person don’t work properly at present, but they’re never requested so it’s not that.
I’ve been comparing this line by line with Mastodon’s output of a Person, but I’m drawing a blank.