@ahmedcharef,
Based on the sample data shared by you the Date passed to the dataPoints is not in standard format. Instead, passing the Date in the standard JavaScript DateTime format new Date("2018-01-07T20:51:05.000Z")
will work fine in your case. Below is a sample dataPoint –
{ x: new Date("2018-01-07T20:51:05.000Z"), y: -6 }
Also, kindly take a look at this JSFiddle for a working sample.
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Indranil Deo
Team CanvasJS