Hi @Anonymous ,
Do you mean that you could not display the Day number value property within the X-axis of your Line Chart control?
Could you please show more details about the Day number value within your collection?
Based on the screenshot that you mentioned, I think this issue is related to the amount of records in your collection. How many records existed in your collection?
As an fixed solution, please consider configure your canvas app as a Tablet Layout App firstly, then set the XLabelAngle property of the Line Chart control to following:
45

then your Day value would be displayed in 45 angle within the X-axis of your Line Chart control.
Please consider take a try with above solution, check if the issue is solved.
Best regards,