Laravel 5.4 - Installing Passport
Most likely you skipped one or two of the following steps:
Next, register the Passport service provider in the providers array of your config/app.php configuration file:
Laravel\Passport\PassportServiceProvider::class,The Passport service provider registers its own database migration directory with the framework, so you should migrate your database after registering the provider. The Passport migrations will create the tables your application needs to store clients and access tokens:
php artisan migrateOnly after that can you run
php artisan passport:install