Dealing with SSRS reporting framework in Microsoft Dynamics 365 Finance and Supply chain can be tricky sometimes.
Recently I get the below error after adding a new dataset to an existing SSRS report.

By doing the below steps the error was resolved. If you are facing the same error then you can try the below steps :
- Build the model under which the report object exists
- Restart SSRS service
- Perform IIS Reset
Have a great day.