Fatal error: Uncaught Error: Interface "Cartalyst\Sentinel\Checkpoints\CheckpointInterface" not found in /home/bookshelter/public_html/vendor/cartalyst/sentinel/src/Checkpoints/ActivationCheckpoint.php:26 Stack trace: #0 {main} thrown in /home/bookshelter/public_html/vendor/cartalyst/sentinel/src/Checkpoints/ActivationCheckpoint.php on line 26