Fortunately, This issue happened due to steam client update...watch this copy this and paste https://www.youtube.com/watch?v=sFeHWyUbHOs and go to 3:12 time stamp this might help you guys.
Hope they [steam devs] solve it.in the same boat unfortunately
wow that's cool..Yeah its been like this for days but ive found a way to play with friends on mac now!
Ive been using "NVIDIA GeForce NOW" since this bug came out; just create an account and yeah just search up Stardew Valley
hope this helps for a while until its fixed