About a year ago I made a post on the same subject: ArcGIS Pro Create Locator fails; I followed up with Bug Fix with Create Locator Tool describing a bug that would be fixed at 2.5; I'm using pro 2.5.1 and I'm getting the same error I did a year ago:
Error happened while transforming data
Failed to execute (CreateLocator).
This time it's with centerlines on a local file geodatabase; I ran the repair geometry tool and it reported it deleted one null geometry but I still get the failure. Just for fun I ran the check geometry tool and it found no problems.
