Issue in Date Format in Laravel

I am using below code.

public function rules()
{
    return [
        'SuspensionHistoryDate' => 'required|date_format:"mm/dd/YYYY"',
    ];
}

below is the value that I tried to post "03/23/2016".

I am getting below mentioned message.

The d l issue date does not match the format MM/DD/YYYY.

Can you please guide if I am missing anything?

via Chebli Mohamed