Can't stop web server in Google App Engine Launcher
I face this issue too. It has to do with the application you are running. If you are sure it runs perfectly fine, then it may be over burdening the server in a way. I strongly recommend logging relevant aspect of your code so it displays any issue in the log console. Hope this helps
I am running development web server in Google App Engine Launcher without any troubles. 
But I can't successfully stop it. When I am press Stop button, nothing happens. 
Nothing adds in logs after pressing Stop.
And after that I can't close launcher. 
The only way to close launcher is Task Manager.
Although when I am using dev_appserver.py myapp via cmd it is successfully stopped by Ctrl+C.
By the way I am under proxy.