Creating outlook event from new task in planner not working

[Anonymous]

I've been trying to create a flow where when a new task is created on MS planner, it creates an outlook event on the personal calendar who the task is assigned to. Currently I have created a flow and when I test it on myself, it works. However, when I assign a task to my colleague, he does not receive any outlook event on his calendar. 

My flow looks like this. 

Really not sure how to troubleshoot this as I am a complete newbie and would appreciate any help!!