Recent Friendica issue following NodeBB Activitypub groups (categories)

@helpers

I noticed a problem that arose recently (no more than three or four months ago).

In practice, when I try to follow a NodeBB Activitypub group (citiverse.it instance) from Friendica (poliverso.org instance), Friendica doesn't recognize the group as an Activitypub actor and gives me this error message.

I'm experiencing this problem with both old and new groups.

For example, with the group @bluesky, which is a few months old, at the link citiverse.it/category/55, it's recognized, but I can't join it. When I try to join, I get this error message.

Exception thrown in /var/www/friendica/src/Module/Contact/Profile.php:197
Stack trace:
#0 /var/www/friendica/src/BaseModule.php(251): Friendica\Module\Contact\Profile->content()
#1 /var/www/friendica/src/App.php(595): Friendica\BaseModule->run()
#2 /var/www/friendica/src/App.php(190): Friendica\App->runFrontend()
#3 /var/www/friendica/index.php(22): Friendica\App->processRequest()
#4 {main}

With a newly created group, for example, the @wordpress@citiverse.it group at the link citiverse.it/category/231, I can't even capture it with the search function; and if I try to insert the link, it only captures the RSS actor.

What do you think the problem might be?

@heluecht @julian