Friendica doesn't use the "!" notation. This is only a notation that a Lemmy, Piefed, or MBIN instance understands.

Friendica instead uses the familiar account notation used by Mastodon, Sharkey, Misskey, etc. It sees the Lemmy community as a user that is also a group.

If you want to follow, for example, the "asklemmy" community at lemmy.world, in the "Add New Contact" box, just enter : asklemmy@lemmy.world, and then click the "Connect" button, and it will find it, and you can follow it like any other account. Friendica will recognize it as a "Group", as opposed to an individual account, and it should show up in your Groups section.

Let me know if this works.

Maybe try searching with @ comunity @ instance? Of course without spacing. Thats how i do on mastodon.

are you using the full domain? '!community @ instancedomain'? ie '!fediverse @ lemmy.world'? minus the spacing of course

BTW, there is a community that you can join from Lemmy, Piefed, or MBIN, that supports my-place.social: https://feddit.online/c/my_place_social