Error code for accept a invitation realm

she can join official realm and accept my invite to join my world though

You be able to join from the Minecraft Realms menu. Once you go that menu you will see a list of realms that is available. Just note you will will need an invitation. Once you get accepted, that Realm
will be available to you.

Minecraft Realms works a little different. You invite the player to join your realm or you give them the invite code. Thus it won't be a random player.

I have the same problem. Settings are set correctly, but my daughter can't connect to Minecraft Realms or even accept invitation.

Hello, You play in realm server? or a Normal Game, maybe that are the problem if you don are member from the realm you can't join , you must be invited and you acept the solicitude in Main menu, solicitude accept.