When loading a DocGen Package in the Lightning Experience DocGen Package Designer (LEDD) interface, a Component Error may occur due to unsupported relationship configurations.
After clicking out of the Component Error, your Relationships in the Relationship Tree do not load.
1. On DocGen Admin tab, turn off the LEDD Interface in Lightning or navigate to Classic to view all relationships and determine which could be causing the error.
2. What relationships are unsupported and how do I determine this?
To Resolve Lookup to Lookup relationship follow this article:
To Resolve Replicating on a Lookup to Lookup relationship follow this article:
Unrelated Data / Stand Alone Relationship