IIS Error "Unexpected error 0x8ffe2740 occurred"

I was getting the following error on taking IIS

"IIS Error "Unexpected error 0x8ffe2740 occurred"

Finally, I discovered that its caused by Skype. It listens to port 80 for incoming call. Now, most of the time IIS starts before Skype starts. So IIS works but if you restart IIS or try to start IIS after Skype is started then you will get this error message.

What I did is

Exit skype -> Restarted IIS Admin service. Then its working fine.

This behavior may occur if a port conflict exists on the system. By default, IIS uses port 80 for HTTP communication. If an application other than IIS is running and is using port 80 on the same IP address, you may receive the error message when you try to use IIS Manager to start the Web site.

You can use third-party tools like TCPView or FPort to identify the other application that is using port 80.