How to fix: "Failed to start the Unity Package Manager local server process"?

This is the error message I am getting:




I think I have given Unity and Unity Hub full access:


I have seen this in Answers which is how I got to the above image, but it didn't fix the problem.


I tried asking Customer Support and they said to post on the forums, so here I am... but I am not sure if this is the right place. Really I just want to get back to working on my game. Any advice is highly appreciated!

 

i have the same issue with unity 2021.3.7f1 but not 2020.3.0f1 (win 7)
i've tried new inbound and outbound rules for firewall
i've tried allow the editor and package manager through firewall
i've even disabled firewall and antivirus entirely
but nothing works