Laravel Errors

SQLSTATE[42000]: Syntax error or access violation: 1071 Specified key was too long
Argument 2 passed to App\Providers\AuthServiceProvider::App\Providers\{closure}() must be an instance of App\Post
laravel 5.5 The page has expired due to inactivity. Please refresh and try again
Testing Laravel Passport OAuth2 page does not work: Authentication Required