Hello,
I have the same problem. I bought 4 licenses for my Sketchup 2021 Pro and they worked on the first seat. Now, when I try to use them on the second seat, it says "Sorry, an error occurred in the communication with Sketchucation".
I have turned off the Antivirus for Windows and still does not work. I have updated the Sketchucation Tools to the latest version and still does not work.
What should I try?