503 Error through Web Server

As we did upgrade from 7.5 to 7.11, when we started the Application Server, it came fine. We were able to access it with in IIS Server by clicking browse*;80 (http) in Actions but when we are trying to access it outside the IIS through IE by giving server name instead of localhost, we get the error 503.
When we click on suite folder through IIS &click on basic settings. we get the test connection. When we are clicking the test connection, we are getting error "cannot verify access to path". Attached is the snapshot. Can anyone guide what can be the issue & how can we fix it?

Thanks in Advance

OriginalPostID-244509