The secWindowsNT security plugin is not available. Please contact your system administrator for details

Hello Experts,

Need your help here.

We are at BOXI R2 SP5. with IIS ;Since Saturday we had been facing issues with Windows-NT plug-in in prod environment, as currently our XI R2 environment is setup with NT authentication.

I am getting error while logging in info-view  "The secWindowsNT security plugin is not available. Please contact your system administrator for details"

Initially "NT authentication is enabled" is ON(checked) but post above error whenever i am trying to un-check and check "NT authentication is enabled" check box under CMC --> authentication ; its not at all updating and finally ended up with page cannot be displayed error.

we do have "Default NT domain" as well as Mapped with NT members group

I did modified web.config file  Installation_Directory\Web Content\Enterprise115\InfoView to be of double check

<add key="authenticationDefault" value="secWindowsNT" />

but still i am not able to see changes reflected either in CMC web-console or got rid of plugin error.

I have gone through cases posted here but didn't find much information. Seeking some one has experienced the similar issue and have solution.

Thanks

Gopal K