401 0 0 15 and 401 2 5 0 IIS Error Windows authentication broken

[sharknado34]

So here is the issue (this is happening to 2 separate web applications by the way): We are trying to set up windows authentication for an intranet site, we have successfully set up other web site projects using this kind or authentication, but now that we are using web application projects (with windows authentication) we are suddenly having issues. The web application is asp 4.5, the server is running asp 4.6. We have windows authentication turned on for web.config and for iis, but some users are getting prompted for login when we have internet explorer set for background windows authentication. The most strange part about this is that some people with credentials and some people without credentials are getting prompted for login while others this doesn't happen at all and they arrive at the proper web page. I am not certain at this point what is causing this to happen. We ended up switching one of the web applications to a web site project, and it suddenly works. For some reason the web application project is having difficulty with windows authentication, while web site projects work just fine with it. When looking through the logs for IIS I discovered the following errors for one user who was having difficulty with the windows authentication: 401 0 0 15 and 401 2 5 0. Any ideas on what is causing thisI have looked far and wide to find what is causing this to no avail. Any help would be greatly appreciated.

[HarryNyquist]

Internet Explorer is probably your first problem. You need to be using Edge (or better yet Firefox/Chrome and just deal with the password prompts).

 

If they report seeing an IIS error page it should show a substatus code https://support.microsoft.com/en-us/help/943891/the-http-status-code-in-iis-7-0-iis-7-5-and-iis-8-0 that might be more helpful. That substatus doesn't come up in the log files unfortunately (because Microsoft).

[sharknado34]

2 minutes ago, HarryNyquist said:

Internet Explorer is probably your first problem. You need to be using Edge (or better yet Firefox/Chrome and just deal with the password prompts).

 

If they report seeing an IIS error page it should show a substatus code https://support.microsoft.com/en-us/help/943891/the-http-status-code-in-iis-7-0-iis-7-5-and-iis-8-0 that might be more helpful. That substatus doesn't come up in the log files unfortunately (because Microsoft).

I have tried it in both chrome and firefox, same result (it also doesn't help that internet explorer also determines the intranet security settings for chrome). We use a mixture of windows 7 and windows 10... the iis log file is where I got those codes from though.