IIS returning 403 Forbidden-Access is Denied when proxied through CloudFlare

Hi All,

I am pretty new to Cloudflare. I have added a new property for my website in cloudflare. I added all the records for the website and just tested if the sites are working with DNS only.

With DNS only all the sites were working fine. But, when I made that Proxied then my website is returning 403 - Forbidden Access is denied.

And the error is of the IIS SERVER. You can see below.

image

I have tried for a millionth time that when I remove the proxy the site is loading and when I add the proxy the site is giving 403 error.

Please Help!!!