Chris,
By default CanvasJS calculates intervals which are multiples of 1, 2, 5, 10, etc. Hence if the ranges that you specify is not a multiple of these values, you might miss out the 0 line.
So, even if you specify these values yourself, you’ll have to specify minimum & maximum such that the range (maximum – minimum) is a multiple of interval – this will solve the problem. Otherwise mathematically it is not possible to include 0.
May I know why you are setting custom minimum/maximum values?? If I know this I can probably suggest you a better alternative.
—
Sunil