Hi @hassan1 and @kgarrison
Yes XAMPP or other developer applications could be causing port conflicts. Apps like MAMP, or Docker for example as well. Certain security applications can cause similar issues too.
To troubleshoot this you can try changing your Router Mode, disabling any such applications, or checking for port conflicts manually.
Stop all sites that are running in Local
Force quit Local
(If using Mac) Run the command
lsof -nP -iTCP -sTCP:LISTEN
(If using Windows) Run the command
What you’ll be looking for here is to see when sites are stopped and Local is properly shut down if there are still programs running on ports 80 and 443. These may be conflicting with Local or the system may be reporting Local is still running.
Once you run that command you should see a list of listening ports. If you see a particular program making use of those ports, you can then kill that process by running
sudo kill -9 XXX where XXX is the PID number of that process. (On Windows you will use
taskkill /F /pid XXX where XXX is the PID number of that process)
There are also some more details around this and other troubleshooting steps at this link if needed: Stopping Whatever Is Listening On Port 80.