Comment Mail Not Working

I’m pretty sure it’s my fault, but I can’t really find where to set it up. I have sent out an emali to my users and that worked fine, but in the log when it tries to send a comment it says it’s failed and there is no name or email listed in there. I thought it had something to do with the settings page i hit the radio button for “on.”

I’ll be glad to give you a login or something if that helps!