SCCM Report prompting for credentials

Scenario:

Your SCCM reports have always worked fine. Out of the blue one day when you run a report it prompts you for credentials. No matter what credential you enter it won't work.

If you run the report from the Report Point server it works fine.

In order to fix this issue follow these steps:

Log on to the Report Point server and open the IIS Manager.

Expand Sites, Default Web Site and click on SMSReporting_SiteCode. Double click Authentication under IIS.

Right click Windows Authentication and click on Providers.

Make sure NTLM is in the top of the list.