@dpanscik,

The datapoint y-value can only accept numeric values as of now. Passing the dataPoints with numerical values as shown in the code-snippet below should work fine in your case,

dataPoints.Add(new DataPoint(new DateTime(2016, 01, 01), new double[] { 656.289978, 657.719971, 547.179993, 587.000000 }));

Kindly refer to our gallery page for an example with complete code.

—
Adithya Menon
Team CanvasJS