What if a multiple Y axis won generate or there is an error?
>> Make sure that the Y axis min, max, and increment is set so that all the labels can fit in a vertical orientation along the Multy_Y axis. For example, if you are using Y axis values from 1,000,000 to 41,000,000 in increments of 5,000,000, then we would not expect it to work (since there is no room for all the numbers written vertically). But if the increment is 10,000,000, then it might just work (or you could divide all numbers by 1000, and list the Y axis label as being in “thousands”). It basically comes down choosing a reasonable for a scale when the numbers are written vertically.
