Activitypub and changed domains

I don’t seem to be picking up activitypub posts from any of my mastodon/fediverse accounts any more.

I moved my forum from https://club.tidalcycles.org/ to https://uzu.lurk.org/ , and think this might well be the cause. I have a feeling that activitypub doesn’t handle changing domains at all well.

I tried destroying and recreating one of the category activitypub actors in discourse, and then resubscribe to that, but it still isn’t working - maybe because the post comes from a user, and is then reposted by the category.

Do I need to reset the plugin and its followers completely, and if so what’s a good way of going about that?