Cross Platform Fail

I'm having problems joining an Xbox series S game from my Steam Deck. Can anyone help figure out why this might be?

We put the joiny code on and we can totally see the name of Xbox world come up. We try to join the game and we get Failed to Connect. We have set a password when we started the world on Xbox, but we aren't even prompted to enter it when we try to join from the Steam Deck.

We're mostly sure the versions are the same. Steam Deck says d1-0.217.31 (n18). Xbox says ss1-0.217.31 (n18), so the last part is the same, but the beginning is different.

We have successfully done this before, but it's been a few months.

We don't have a cross platform option showing when we set the game up on the Xbox.

Kids have all kinds of permissions to allow them to play multiplayer games, so that's not the issue.