Http request Smuggling

In fortify scan they given this request  https://whatis.techtarget.com/ 4ca68bglossaries

with some header  and also given response 404 and also we getting 404 and unable to take trace of this url because some added part in url 

But our actual proxy url is whatis.techtarget.com/glossaries

Which giving sucess response we can not replicating the fortify scan reports which they mentioned in response as  we  getting 404 what we should do in this scenario