HELP! Dashboard chart widget will not update data source


I am getting an error ONLY SOMETIMES when I try to update the data source on a chart widget. I select the new data and when I try to save, it says "Selected data cannot be charted. Please select a new range." I am doing this for many dashboards, only some have issues though all pull from same sheet with same formatted data.

Any ideas? I am on a time crunch to get this updated, going crazy without a solution! Thanks Smartsheet brain trust.