Minecraft online still not working

No, in any friend world. We all have NAT open.

Is it that one particular friend? Have they checked their account settings, or the settings for that world? It's possible the issue is not on your end. I would test by trying to join another friends "world" and see if that causes the same results?

One thing I would do is have each of your friends create new worlds and test connecting, including the friend with the world you're trying to join, to test if you can get into any of their worlds. This can help us identify if it's a problem connecting to
that one friends world, specifically that world, or if this is an issue of connecting to any world.

Let us know the results and we can figure out where to go from there.

Few things. What platform are you playing on?

Do you have the settings enabled to allow you to join multiplayer? Cross-play? And the ability
to "Create and join clubs" (since that is how Minecraft handles Realms).

Is your friends instance a world, server, or realm?

The answer to these questions can help us identify what the solution is to fix your issue.

Alternatively,https://www.youtube.com/playlist?list=PL3UcuLp6uKBITiiau8vCEhTyCSwrekUgZ

Playing on Xbox One

Yes, i have all theses things ok

And the problem is only when we try to join other friends worlds, but in servers and realms it works.

About the crossplay, i bought the game for android for knowledge about if i could join my friends game from the mobile to the xbox. Didn't worked either.