I know this thread is to old but I can't believe that 6 years later there is no solution.
I have Pro Tools 2022.7.0 and I tried collab a few times and I have the same problem every time: "Failed: Couldn't connect to server". The task manager recognizes the tracks that I try to share and the ones that want to share with me but it always gives me the same error.
If anyone was able to fix it I would be very grateful
Thanks in advance.