流明:为什么在本地服务流明应用程序时无法同时调用多个路由

I am serving my lumen app locally using the following command as mentioned in Lumen documentation:

php -S localhost:8000 -t public  

I have multiple routes in my web.php file whereas each route calls a particular function and all the functions are under one controller.

When I call each route individually, I have no issue and it's running and processing everything as expected. However, when I try to call 2 routes or more simultaneously, only the first one runs as expected while the rest keep just loading without doing anything. The way I know that the other routes aren't doing anything is because I log something right at the beginning of each function.

If this helps, I'm running the app on my local environment and I'm not using Valet or Homestead or anything similar. Besides, I'm a Mac user; so could this have to do with some configuration that I'm missing?