Help! Multiplayer Issues

I am on Steam more specifically Mac, and my friend is on PlayStation, they have gotten to the Space Anomaly and should be able to join me. But it isn’t working.

I added their friend code fine but when they add mine it says unable to add friend rn. Although my thing did pop up for them.

I still can’t join them or they join me.

They have ps plus so they have online. I’ve tried using both hosting a session what could be the issue and how can I fix it?