What is the proper way to setup Steam online subsystem with Mac?

My project is configured to use the Steam Online Subsystem, and works perfectly when deployed on two PCs. They are able to host games, view servers, and join. However, on a Mac everything stops working. I’ve loaded the game into Steam via ‘Add a Non-Steam Game’ and run it from there and can see the Steam overlay pop up. When I try to host a game and view servers, no servers pop up and I cannot connect.

I’ve tried searching for documentation on this, but can’t find anything. Is there something I have to do differently to get Steam’s subsystem working on a Mac? Thank you!