I can not access localhost using specific port. for example I can access localhost using port 5010 but can not access using port 5040. Error said below: The site could be temporarily unavailable or too busy. Try again in a few moments. If you are unable to load any pages, check your computer’s network connection. If your computer or network is protected by a firewall or proxy, make sure that Firefox is permitted to access the Web.

FYI, it is working using other browser for example edge or chrome