One or More Datasource Credentials Required to Run the Report Have Not Been Specified - SoapException

I kept getting the error:

One or more datasource credentials required to run the report have not been specified

when I was trying to run an SSRS report. Turns out I needed to set the MSCRM_FetchDataSource to Windows Integrated Security (as that’s how I was accessing the reports). Must have missed that when I was setting up SSRS!

Edit May 30th/2012

I’ve decided to update this post as I feel it might be a little misleading. By default

MSCRM_FetchDataSource should be set to Credentials supplied by the user running the report by default. If you don’t have it set to this the out of box reports won’t run.

My plugin was using Windows integrated security as it’s authentication type, however if it’s set to Credentials supplied by the user running the report by default.

So I actually ended up going with Credentials stored securely in the report server with Use as Windows credentials when connecting to the data source checked, along with specifying a user. This allowed the out of box, and the CRM plugin to run (as the auth was stored on the server).