[2021] Can't build in Fortnite save the world on Xbox Series X

Hello, I don't play fortnite, but my little brirtger loves it and got an Xbox series X flr Christmas, and now he has also gotten Fortnite save the world, and he was really happy about it, but the the problems came, he cannot build anything while he plays, he has all the materials and the buttons on the controller works just fine for anything other than building, have any one else had this or a similuar problem?? And how did you fix this?? It is it some software problems that epic games have that may be fixed in future updates??

Thanks in advance