Help with Steam Remote Play Together

[Princess 20-Sided Die]

I've been trying to set up Remote Play Together with my niblings but it hasn't been working. First, it was showing their account as offline when they were online and when I tried to send an offline invite to the game, they couldn't find an invite anywhere. I know my computer is fine, but they're using a Chromebook laptop and I'm not sure if that is enough for them to join me or not, so that's my first question, if it should work on their Chromebook. My next question is if it should work, why isn't it. They were able to download the Steam app and were logged in and using it (not the browser) when I tried to invite them to my game. Is there anything else we need to download to their laptop? (The xbox gaming software?) Also, they have access to a PS4 as well, can we do Remote Play Together on there? (They do not have a PS4 membership to be able to play online, and that also requires we both own the game, which is cost prohibitive.)

[Ettanin]

Maybe try later again. Steam usually has maintenance around this time once a week.