Laravel php artisan class log does not find

centos7.0

laravel 5.1.11

php7.0

"php artisan" message:

    Fatal error: Uncaught ReflectionException: Class log does not exist in /home/website/vendor/laravel/framework/src/Illuminate/Container/Container.php:741
Stack trace:
#0 /home/website/vendor/laravel/framework/src/Illuminate/Container/Container.php(741): ReflectionClass->__construct('log')
#1 /home/website/vendor/laravel/framework/src/Illuminate/Container/Container.php(631): Illuminate\Container\Container->build('log', Array)
#2 /home/website/vendor/laravel/framework/src/Illuminate/Foundation/Application.php(674): Illuminate\Container\Container->make('log', Array)
#3 /home/website/vendor/laravel/framework/src/Illuminate/Container/Container.php(842): Illuminate\Foundation\Application->make('log')
#4 /home/website/vendor/laravel/framework/src/Illuminate/Container/Container.php(805): Illuminate\Container\Container->resolveClass(Object(ReflectionParameter))
#5 /home/website/vendor/laravel/framework/src/Illuminate/Container/Container.php(774): Illuminate\Container\Container->getDependencies(Array, Array)
#6 /home/website/vendor/ in /home/website/vendor/laravel/framework/src/Illuminate/Container/Container.php on line 741

via Chebli Mohamed