I'm hoping someone might be able to help me or point me in the right direction.
I am trying to create a scheduled monthly issues called 1:1s which has a number of subtasks with peoples name which is assigned to their line manager and due within 10 working days. Ideally I'd like this to trigger on the 1st of the month.
I have been trying various things for an hour based on other help messages. This is what I've made:

But I'm getting this error:

If anyone could help I would be extremely grateful.