Hi!
According to the text error, you must have an action block called 'Get Principal ID' that provides an array as its output somewhere in your flow, but I cannot see it on the screenshot you shared. Maybe inside the 'Apply to each'?
I would suggest you to share a screenshot from your flow design, and remember to expand the relevant action blocks by doubleclicking on them, so we can figure out their input details
Thanx!
