This section shows a couple of techniques for fixing problems related to report generation.

ReportWatcher service not running

A modernized application require a ReportWatcher service running to render reports. See the previous section on configuring this service.
If a modernized application is running without an active ReportWatcher service, the control that should display a report will look like the following image:
In the browser developer tools a failed request should be displayed related to this problem:

Error during report rendering

The console of the ReportWatcher service displays errors that may occur during report rendering.

Inspecting generated RDL

If there is something that is not being rendered as expected it may be useful to inspect the generated RDL document . To do this a setting can be enabled in the Web.config of the ReportWatcher service to dump report definitions to a directory:
This directory is going to have files with the RDL that will be used to render the report:
This report definitions could be inspected using a text editor or the ReportBuilder tool.

Tracking exceptions inside ReportViewerControl

It may be useful to get a hint on an internal error that occurred inside ReportViewer. To get inspect exceptions being raised while the report is being rendered, attach a debugger to the ReportWatcher service and disable the "Enable Just My Code" Visual Studio setting: