Exception thrown on post request

I am breaking out some code from a laravel app to make a simpler app using lumen and I'm running in to an issue with a post route. When posting to it from a form I get this error:

MethodNotAllowedHttpException in Application.php line 1208:

in Application.php line 1208
at Application->handleDispatcherResponse(array('2', array('GET'))) in Application.php line 1163
at Application->Laravel\Lumen\{closure}() in Application.php line 1390
at Application->sendThroughPipeline(array(), object(Closure)) in Application.php line 1164
at Application->dispatch(null) in Application.php line 1104
at Application->run() in index.php line 28

The routes.php file looks like:

// $app->post('contact/submit', 'ContactController@submit');
//simple route to make sure the problem isn't in my controller
$app->post('contact/submit', function () {
    return 'Hello World';
});
//catchall
$app->get('{page_slug:.*}', 'CmsController@page');

I uncommented eloquent and dotenv in the app.php, but otherwise it's a pretty basic lumen install and I'm not sure where the problem is... Any help would be awesome.