Your trend chart has to have at least on X-axis and one Y-axis. At times, you may want to configure more that can be used instead of either default axis.

Option 6.1	Configure the X-axis.
Option 6.2	Configure the Y-axis.
Option 6.3	Create a new axis.
Option 6.4	Map axes to a line.

More information

Configure a Trend Chart.

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