Some recipients not receiving confirmation email autoresponders

Is the confirmation email issue with Delta Airlines still being investigated?  Just want to make sure we're advised of any updates regarding this.  Thanks.

Thank you for contacting us.

So far we were not able to confirm the issue. According to the account email history the messages are being successfully sent.

If you can still reproduce it using some specific email address, please let us know. It is also advised to check the Spam/Junk folders.