flow test on a sharepoint empty field

Hello,
I've a list in SharePoint and when a line is add or modified I want to test if a specific field [TacheID] is empty, if true I want to create a planner task.

I've an error: Can't read property "properties" from null or not defined expression (I translated from French).

if I send this "@equals(length(string(triggerBody()?['TacheID'])), 0)" by email I get True or False