Yes that is correct. Reinstall, open the rules of firewall and antivirus if it is interfering and lastly restart.
Well first try that out, if it does not work maybe you are in an outdated version of the beamMP or and need to downgrade the current version of beamNg(shouldn’t be necessary).
Also didn’t mention if your windows is on 32-Bits or 64-bits.
We will work something out, just guide me through your steps.