Q:

AuthenticationType Negotiate vs NTLM

I have the same code base used on 2 different sites hosted on the same server (IIS 7.5). 
For some reason, when I check the Identity.AuthenticationType property on the code behind of an http handler I see NTLM for 1 site and Negotiate for the other. This is causing some problems and I need both of them to use NTLM.
Could you help me to figure out why this difference? So far I see both IIS sites are configured on the same way but of course there is at least 1 difference that I couldn't detect.
Thanks!
EDIT
I've used this link that provides instructions to remove "Negotiate" provider from IIS. It didn't work for me. I executed
appcmd.exe set config "Contoso" -section:system.webServer/security/authentication/windowsAuthentication /-"providers.[value='Negotiate']" /commit:apphost

Maybe I did something wrong, but it didn't help. I still see "Negotiate" as AuthenticationType
The problem I have is that I'm setting on web.config impersonation credentials but it's not using them. Instead of using credentials I provide, it uses the anonymous user.
And something weird is that windowsAuthentication is disabled. I thought "Negotiate" was only used by windowsAuthentication.

A:

Negotiate will choose either Ntlm or Kerberos authentication internally.
If the site says Ntlm only Ntlm authentication would be choosen.
Please check both the site and make the authentication has same.

