Error "The request failed with HTTP status 401: Unauthorized." when accessing the Quest Knowledge Portal or Quest Knowledge Portal.
This is caused when the SQL Reporting Services (SRS) and Quest Knowledge Portal are installed on separate servers and the Quest Knowledge Portal is accessed remotely. The user is unable to authenticate due to an issue with 2-hop (aka double-hop) authentication.
In some cases, "<RSWindowsNTLM/>" may need to be remove from the rsreportserver.config file so that it appears as:
CMD: Setspn -A HTTP/<System Name> <Domain\Service Account>