Hey Sofian,
Is it possible to test this with a breakpoint?
Depending on the size of the list you're retreiving, this is what I would do: use my data source flow first as a subflow to return a boolean (isListEmpty) in a helper object and show an alternative message for users. If it's not empty, then I call the data source flow a second time to show the contents of the list.
Good luck with the error!