Work.com: Coaching - Why do I get an 'invalid object or field' error when customizing a coaching report type?
|Knowledge Article Number||000220864|
|Description||Why do I get an 'invalid object or field' error when customizing a coaching report type?|
|Resolution||You are likely getting this error if you've added lookup fields for both the coach and the person being coached. You cannot add lookup fields from multiple records of the same type. In this case the object type is User and the records are the person being coached and the coach.
There are a couple of workarounds to consider:
Create a Joined Report
Create Custom Fields
How do I create custom fields?