Continuous password prompt in outlook-vault cache

 Hi All,'

We are using Exchange 2010 and EV 9.0.2 /SQL 2005 sp-4

Most of our users are getting continuous password prompt while vault cache is synchronize in the backend

We exclude Enterprise vault server i.e. http://evserver.com in our internet explorer proxy setting through windows group policy

But still problem persist and even if user provide the credential it was not accepted and continuously prompted the same.