That sounds great 
You can change the log level to info now in the isapi_redirect.properties
Another thing whenever you access your application and page takes too much time to load or page gives you some standard error like 500, first of all check the application pool of the application/website whether it is running. As Application pool is responsible for providing resources for your application. Also, whenever new website starts working and old are not, just change the app pool of old site to the new app pool and if you try the same at your end now that will also work.
Have a great day ahead
Thanks
VJ 