[iis-7] Bad Request - Invalid Hostname IIS7

I'm not sure if this was your problem but for anyone that's trying to access his web application from his machine and having this problem:

Make sure you're connecting to 127.0.0.1 (a.k.a localhost) and not to your external IP address.

Your URL should be something like http://localhost:8181/ or http://127.0.0.1:8181 and not http://YourExternalIPaddress:8181/.


Additional information:
The reason this works is because your firewall may block your own request. It can be a firewall on your OS and it can be (the usual) your router.

When you connect to your external IP address, you connect to you from the internet, as if you were a stranger (or a hacker).
However when you connect to your localhost, you connect locally as yourself and the block is obviously not needed (& avoided altogether).