Thanks for contacting Syncfusion support.
On further analysis of the shared screenshot, the mentioned problem occurs only when the shared datasource specified in the RDL report in not created in your Syncfusion ReportServer. So, can you please ensure whether the shared datasource used in your RDL file is available in your Syncfusion ReportServer. If the shared datasource is not available in your ReportServer then, create a Shared datasource in your Syncfusion server to avoid the mentioned problem at your end.
If the issue still priests, then share screenshot or video of the datasource configuration detail of the RDL file to validate the mentioned issue at our end.