HTTP Service Is Too Busy Error!

An Error you may face is when you try to run a simple SharePoint Management Shell Command, it gives you an error saying :

The HTTP service located at http://localhost:(portNumber)/securitytokenserviceApplication/securitytoken.svc is too busy.

And no commands were working at all.

In this case check the Application Pool for the SecurityTokenServiceApplicationPool, you’ll notice it’s stopped, start it and try again.