The client is unauthorized due to authentication failure

Are you using Neo4j Desktop? If so you can go to Open Folder -> Import to access the import directory, it's db-specific and pretty heavily nested e.g.

/Users/terry/Library/Application Support/Neo4j Desktop/Application/neo4jDatabases/database-92b8ad30-b044-47e4-babf-f4a3ac491877/installation-3.5.3/import