You might have come across this issue while setting up LumenPassport
When you are listing routes via php artisan route:list
Error:
Error: Call to undefined method Laravel\Lumen\Application::group()
Solution
In your AppServiceProvider boot replace
\Dusterio\LumenPassport\LumenPassport::routes($this->app);
by
Dusterio\LumenPassport\LumenPassport::routes($this->app->router)
It's also depends, in which service provider did you place this in your app.
This will fix the problem.