I assume this isn't the only user trying to login from AD, correct? 
Then compare the properties/settings between a working and the 
non-working user, you should probably find something. Also enable 
debug logs in keystone to find more details. And by "all of a sudden" 
you mean that it worked before? So what changed between then and now?

Zitat von Adivya Singh <adivya1.singh@gmail.com>:

> Hi Team,
>
> There is one issue , where a user is getting " Authenticated Failure" all
> of a sudden, and this user is the only user who is facing this problem.
>
> I tried to disable and enable the project if, Check the logs but do not
> found anything related to Keystone authentication
>
> Delete the Project id and Create it again , Results are same , Any insights
> what i can do more to fix this issue
>
> Regards
> Adivya Singh