Bad Request (Invalid Hostname) when accessing via IP

Customer wanted to have a dedicated IP, but once I change the IP from the plesk control panel, I couldn’t get the website when accessed using IP. Instead, it was giving me the plesk control panel’s default page. Reason ? Default Website was having the IP as “All Unassigned”. Set that to the main IP address. But after that I was getting a new error.

What I could get was “Bad Request (Invalid Hostname)” in bold letters. Here is what I did to fix the same.

Start -> Run -> inetmgr -> Expand the (+) -> Websites -> Right click on the domain name -> Take Properties -> Website -> IP Address (make sure that it has the dedicated IP assigned there) and then click “Advanced”

Add/Edit Web Site Identification

IP Address : Choose the dedicated IP from drop down list
TCP/IP Port : 80
Host Header Value : Leave it blank (Important)

Leaving the Host Header Value should fix the issue and fetch the website when accessing it using the IP.