Answers for "Target class [AuthorsController] does not exist in laravel"

Target class [SallyController] does not exist.

//In laravel 8 uncomment  protected $namespace='App\\Http\\Controllers';

Target class [AppController] does not exist.

public function boot()
{
    ...

    Route::prefix('api')
        ->middleware('api')
        ->namespace('App\Http\Controllers') // <---------
        ->group(base_path('routes/api.php'));

    ...
}