Laravel 5.1 Session auto expire even user cannot logged out

I am working with laravel 5.1. After login the session is expired after several minute without logged out by user.

I found one solution to change the name of cookie in config/session.php laravel_session to lerevelsession by removing underscore.

My config/session.php file is:

return [
'driver'          => env('SESSION_DRIVER', 'file'),
'lifetime'        => 120,
'expire_on_close' => FALSE,
'encrypt'         => FALSE,
'files'           => storage_path() . '/framework/sessions',
'connection'      => NULL,
'table'           => 'sessions',
'lottery'         => [2, 100],
'cookie'          => 'laravelsession',
'path'            => '/',
'domain'          => NULL,
'secure'          => FALSE,];

What is the problem that i can't figured out?

via Chebli Mohamed