X_PRELOAD_UNKNOWN_RELATION
Means
no relation of that name on this entity
Typical cause
a typo, or a relation the schema never declared — relations are derived from references() columns, so there is no list to read them off
Fix
the fix is a call on one that exists, e.g. relationNamed('posts', 'author') # or: org, likes. No foreign key at all ⇒ x entities list --json, then add .references(() => <target>.id) to the column that points at one