The report is a document processed and render on the server with the assigned to it data. In general there are no limitations for the used data as long as the machine has enough memory and CPU to handle the document generation - Performance Considerations
In your case, my recommendation is to use Fiddler and check the Inspectors - Response - Raw tab to check the actual response. Then check the server's Event Viewer for any error logs. The actual exception's stack trace will be helpful to identify the problem and troubleshoot it.
Test also the suggestions from my previous post and let us know the result of each and the logged exceptions.
Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.