CRM 2011: Report cannot be displayed

If you are getting the following error while trying to run a CRM 2011 out of the box report:

Full Stack: [ReportServerException: Immediate caller DOMAIN_NAME\executionAccount has insufficient privilege to run report as user S-1-5-21-1842424028-......] 

[ReportServerException: Cannot create a connection to data source 'CRM'. (rsErrorOpeningConnection)] 

OBS: For this scenario, I am considering that you have the SSRS server installed on a different server.

Here are some of the things you can try:

SCENARIO 1: You only have CRM 2011 reports in your SSRS reporting server: 

1. In Reporting Service Configuration Manager, uncheck the 'Specify an Execution Account'. 
2. Browse to both SharedReports\5.0.xxx\ and _MSCRM report folder and make sure that MSCRM_DataSource connection Data Source Type is set to Microsoft Dynamics CRM Sql and the connection is using the Credentials Supplied by the User running the report (uncheck the Windows Credentials box).

 SCENARIO 2: SSRS is in a shared environment, where the execution account needs to be used:

1.  Add Execution Account to CRM's PrivUserGroup in AD. 

You can obtain more information here:
The Report Cannot be displayed RsProcessingAborted CRM 2011

Add Execution Account to PrivUserGroup