Steam: Unable to Enable Multiplayer or Form a Party with Friends

We've received reports from players on PC having issues matchmaking with friends and receiving the error message There was a problem sending the invite, please try again later. 

Workaround:

• Unlink and relink your SHiFT account from your platform via https://shift.gearboxsoftware.com/home
• Double check that you don't have who you're trying to group with blocked on your Steam account.