Our help desk is often approached with concerns that the generated report is empty and does not display the hours on the time sheet. Often, the concern is due to the fact that the report is configured so that it only displays the hours confirmed on the timesheet, but they have not been confirmed in advance, i.e., the desired working hours do not make it to the report.
If the previous setting was correct and the hours still do not appear in the report, it is also worth checking which data you used when generating the report. For example, if you chose schedule data as the source data but you do not plan a schedule from which the data would reach the report, the report generated by you will be empty.