Well I didn't get a successful install on Debian, RPA and HC Sim couldn't see each other. I'll have to try something else...
A thought in the meantime, I wonder if this is a manifestation of a peculiarity I observed years ago. If the port used by RPA is not being released by your system when you close RPA when you reopen RPA it won't be able to get that port and it won't be able to connect; at least this was the behaviour in 2021 (I doubt it's been fixed.).
You should be able to test for this in the terminal (I haven't checked this myself yet). Open RPA and then type in the terminal "netstat -tunlp" without the quotes (you may have to use sudo). Your looking for a entry under local address with the port 4608, and a foreign address that starts with 99. If you have it then close RPA and type the netstat command again, that entry should be gone.
- Tim