- Posted by Shay Friedman on September 1, 2012
The Problem
I was working on a web site on my local computer. When I wanted to run the web site on my local IIS, I suddenly received a 404 Not Found error for everything hosted on my local IIS.
I tried to run iisreset (even twice, of course!) and it didn’t help. I then tried to start debugging from within Visual Studio, just to see what happens – then I received the OMFG error: “The Server Committed a Protocol Violation. Section=ResponseStatusLine”.
What?!?
I turned to my old friend, Google. He (or she?) helped me find Martin Kulov’s post - http://blog.kulov.net/2006/06/server-committed-protocol-violation.html, which suggested that some application had already been using port 80 (the one IIS is using). This results in IIS not being able to load and eventually throwing all of these doomsday errors.
The Solution
I downloaded TCPView to figure out which application is responsible for all the mess. I was surprised (or not) to find out which application it was:

It was SKYPE!!!! WTF???
Killing Skype and restarting IIS solved the problem and I was able to go back to work.
Note: I’m using Skype 5.10.0.116.
All the best,
Shay.