Data-Driven Subscription Fails but Report Runs Manually

In a continuation of my last blog post on Finding Report Subscription Errors, there was a tricky little reason why the subscription was failing for some of the parameter values, even though the reports could all be run manually.  Just like the Current User Filter in SharePoint, it is CASE SENSITIVE.

I got this error in the trace log:

library!WindowsService_113!308!05/29/2012-10:31:17:: e ERROR: Throwing Microsoft.ReportingServices.Diagnostics.Utilities.InvalidReportParameterException: , Microsoft.ReportingServices.Diagnostics.Utilities.InvalidReportParameterException: Default value or value provided for the report parameter ‘Manager’ is not a valid value.;

But all of the values being fed to my subscription were valid values which worked when manually running the report.  Why did some of the reports in the subscription render successfully and others not?  It turns out the underlying query in SSRS for the Manager parameter dropdown had a mix of either lowercase or the first two letters capitalized. The query I was using in my data-driven subscription was all lowercase.  So only those in the report dropdown which were lowercase were running successfully. 

I solved the problem by changing the underlying query feeding the SSRS Report Parameter to lowercase, and ensuring that my subscription query was also lowercase.  This resolved all the errors.