into their searchbar, try to fetch it and see if it throws any kind of error in the logs? I wanna investigate why Mastodon does not like my objects, and I have no admin access to any Mastodon instance
outbox, followers, and following are returning html (errors). I think masto probes and uses these endpoints to build the profile badge. It might be OK if they don't exist, but I'm guessing that sending html to a json parser could be throwing an exception someplace.