In an effort to increase security, Microsoft has blocked modern applications from connecting to localhost by default.
Fortunately, there is a temporary workaround available. Please run this command in command prompt after installing Nightingale:
checknetisolation loopbackexempt -a -p=S-1-15-2-2472482401-1297737560-3464812208-2778208509-1273584065-1826830168-474783446
If you continue to see connection errors to localhost after running the above command, try disabling SSL validation in Nightingale's settings. This is often needed when connecting to a local IIS Express server.
We apologize for the inconvenience, and we appreciate your understanding as we work towards a better solution.
