I have been searching for this error all over the internet but no matter what I try to fix this problem nothing actually works. And the detailed message that I got after I copied a url from fiddler and put it in the browser and is as follows.
Module IIS Web Core
Handler Not yet determined
Error Code 0x80070003
Config Error Cannot read configuration file
Config File \?\C:\inetpub\wwwroot\myservices\web.config
Actually what has happened in the past that I had this service called "myservices" working all fine when I used visual studio to create a virtual directory for it in IIS. But then what I did, I tried to do a web deploy of this service in IIS and removed ("myservices" from Default Web Site tree which I had created by creating a virtual directory from within VS 2013). And what I observed is, that after I web deployed "myservices" it didn't work the same way as it was working previously when (I created a virtual directory for "myservices" in IIS through VS2013 but had it removed to see whether the web deployed version of it would behave the same way). Therefore when I analyzed the cause of HTTP error 500.19 through Fiddler (for the web deployed service) it said (Config Error Cannot read configuration file and Config File \?\C:\inetpub\wwwroot\myservices\web.config) but when I physically try to look into the folder C:\inetpub\wwwroot I could never find myservices folder as such (what to talk of web.config file in it). Then I manually created a folder called "myservices" in C:\intepub\wwwroot directory and put my web.config file there to see if the web deployed service would still work, but it didn't. Then I removed this folder called "myservices" and obviously the web.config file inside of it and also removed the web deployed service from Default Web Site Tree.
And now after all this mess even if I go to visual studio and try to create a virtual directory for my service "myservices" (I can see it in Default Web Site Tree in IIS ) but it would throw the same error as http 500.19 as the web deployed version of this service. In other words whatever I tried it messed up my services even when it's not a web deployed version which previously was not the case. I literally request everybody out there to please guide/suggest me with whatever experience they have as to what went wrong in all this trial and error endeavor of mine.
This may be a long shot, but sometimes web.config files get corrupted (our code repository occasionally does this) and you cannot see it with the naked eye. take a simple web.config file that you know is not corrupt and start rebuilding the file from there if it works. We have also used a hex editor (like XVI32) where we can see the corruption, but its much easier to rebuild from a fresh file.
If your problem is not the web.config but the virtual folders, then do the same methodology. Start over with what works and go from there. It could be the web deploy tool that is causing the corruption.
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