Laravel 5.1 Mail::raw works but Mail::send doesn't

I am using Laravel 5.1 email with Amazon SES.

If I use:

Mail::send('mymail', function ($m) use ($user) or Mail::send('mymail', $data, function ($m) use ($user) It doesn't work. I get a 500 error.

However if I use:

Mail::raw('Hello this is a test message', function ($m) use ($user) it works fine.

Any thoughts what could be causing this?

via Chebli Mohamed