AWS s3 File uploading failing via Laravel

I'm running a Laravel app with a code like this in one of my controller functions:

$s3 = Storage::disk('s3');
$s3->put( $request->file('file')->getClientOriginalName(), file_get_contents($request->file('file')) );

I believe Laravel utilizes Flysystem behind the scenes to connect to s3. When trying to execute this piece of code I get an error like this:

The Laravel docs isn't giving me much insight into how/why this problem is occurring. Any idea what is going on here?

via Chebli Mohamed