[@projectmoon@forum.agnos.is](https://community.nodebb.org/user/projectmoon%40forum.agnos.is) hmm... could be a bug in the user migration code path. Can you run your forum in dev mode (`./nodebb dev`) and try to load some of the categories here in your forum, and let me know if you see any errors in the console?

[@julian@community.nodebb.org](https://forum.agnos.is/user/julian%40community.nodebb.org) could not run it in dev mode directly because of docker compose, but did set `NODE_ENV` to `development` and got verbose logs. Only thing that shows up is: ``` 2025-05-03T19:35:59.553Z [4567/53] - warn: Route requested but not found: /category/activitypub@community.nodebb.org ```

So, this URL does work: https://forum.agnos.is/category/nodebb-development@community.nodebb.org Maybe it has something to do with the activitypub category being a sub-category of nodebb development?

[@projectmoon@forum.agnos.is](https://community.nodebb.org/user/projectmoon%40forum.agnos.is) no, that didn't matter. There is no concept of nested categories in ActivityPub yet. But the issue seems legitimate, I can't access the ActivityPub category from a test Mastodon server either.

[@julian@community.nodebb.org](https://forum.agnos.is/user/julian%40community.nodebb.org) I was able to access it from a Lemmy instance. So it is federating, at least partly. But interesting to know that Mastodon has issues with it... One thing that might be helpful is that NodeBB gives an invalid ID error when trying to follow the category via the sync function in admin settings. Stack trace shows it's the error being thrown when trying to follow (activitypub.js line 43).

[@projectmoon@forum.agnos.is](https://community.nodebb.org/user/projectmoon%40forum.agnos.is) thanks, can you try again? For whatever reason the handle-to-cid association was lost, and I'm not sure why. I've manually restored it now.

Yep, shows up now on my end. Maybe check other categories too?

Were there other categories breaking?

[@julian@community.nodebb.org](https://forum.agnos.is/user/julian%40community.nodebb.org) Yes, maybe? https://forum.agnos.is/category/bug-reports@community.nodebb.org for example. Maybe it's not federated? Since I don't see anything about what fediverse handle to use like in the ActivityPub forum.