User Authentication in ZRS against Active Directory

The Zenworks Reporting Server has been configured to use Active Directory as user source.
The connection to the user source has been tested and confirmed to work properly.
The users in Active Directory are not able to login into Zenworks Reporting Server.
(It may happen that some users are able to login and some aren't)
The error as shown on the login interface

Invalid credentials supplied.

Could not login to JasperReports Server.

By default Zenworks Reporting Server uses the sAMAccountName to authenticate against Active Directory.
Often the sAMAccountName is different than the logon name.
Please use the the sAMAccountName of the user to authenticate to Zenworks Reporting Server.