Saying 'oh it's okay, it's okay' is not the best way to handle his aggressiveness... he is then thinking 'oh, it's OK to bark and snap like this'. You need to possible keep Max on a leash under control when you have company, and correct him when he does bark/snap by a quick snap of the leash, and then reward him immediately when he stops the unwanted behavior. Use treats, and noise that gets his attention (squeaker, clicker, etc) and praise, praise praise.
Good luck!