Our loadbalancer looks for "loadbalancer.html"
So today, I deleted the file, but in a browser I could still fetch it.
My eyes crossed, I made sure, 3 ways, that the file was removed from the iis web site home dir. But fetching it gave a nice 200 http response, and the file.
In desperation, I created a new loadbalancer.html, and put some test text in it, and then this new content was retrieved, and then I deleted this file, and THEN it finally gave the 404 as desired.
How can I better understand/control this ?