Laravel Queue not work

I used laravel 5 and Queue. try this

$job = (new InstallTheme())->onQueue('install_theme')->delay(20);
            dispatch($job); 

not work

$job = (new InstallTheme())->delay(20);
        dispatch($job);

work

Why the first option does not work?

from Newest questions tagged laravel-5 - Stack Overflow http://ift.tt/2i8QauC
via IFTTT