NovaView Web Access, Flash Analytics and Dashboard all are Web Applications, working through IIS (Internet Information Services). They designed to work with Windows Authentication and if Panorama Web Site isn't configured correctly, the end user might experience an authentication issue such as credentials screen:

Typing the credential screen usually does not not help, and the user receives "HTTP Error 401.1 - Unauthorized: Access is denied due to invalid credentials"" error. 

As a first step, make sure all client pre-requisites are fulfilled.

Then, check that all Panorama Web Site configured to work with Windows (Integrated) Authentication only.

If you have to work with Anonymous Authentication, please consult Panorama Support Team first.

This issue is usually associated with IIS authentication type definition, and it can beeasily resolved by following the following Microsoft KB:

http://support.microsoft.com/kb/871179

Furthermore, Microsoft provides a tool to diagnose authentication issues: Authentication and Access control Diagnostics that helps to check permissions of a given user. 

This software can be downloaded here:

http://support.microsoft.com/kb/907273