I thought that if I entered a Fediverse address here, like '@FrankM@nrw.social,' it would follow that user, and their posts would then appear in the corresponding category.
But that's not happening. There's also no meaningful error message. The actor you see in the image probably appears because I entered an incorrect address.
Does this feature need to be enabled on the Fediverse instance 'nrw.social'?
Who can help?
It's automatic. But you might need to refresh the page before you see the result. Following an actor involves sending a follow activity and then waiting for an accept activity to be sent back. In Lemmy it should be sent almost immediately.
Some personal Mastodon accounts have manual approval of followers but that doesn't apply here. Still, the same communication happens under the hood.