iOS MFMailComposeViewController发送邮件但未收到

Code:

码：

 if ([MFMailComposeViewController canSendMail]) {

     MFMailComposeViewController *mail = [[MFMailComposeViewController alloc] init];
     mail.mailComposeDelegate = self;
     [mail setSubject:@"Sample Subject"];
     [mail setMessageBody:@"Here is some main text in the email!" isHTML:NO];
     [mail setToRecipients:@[@""]];

     [self presentViewController:mail animated:YES completion:NULL];
 } else {
     NSLog(@"This device cannot send email");
 }


- (void)messageComposeViewController:(MFMessageComposeViewController *)controller didFinishWithResult:(MessageComposeResult) result
{
    switch (result) {
        case MessageComposeResultCancelled:
            break;

        case MessageComposeResultFailed:
        {
            UIAlertView *warningAlert = [[UIAlertView alloc] initWithTitle:@"Error" message:@"Failed to send SMS!" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
            [warningAlert show];
            break;
        }

        case MessageComposeResultSent:
            break;

        default:
            break;
    }

    [self dismissViewControllerAnimated:YES completion:nil];
}
 if ([MFMailComposeViewController