I'm testing something where I send an sms message phone to an email address. That mailbox then replies back with a 'Your message has been received' auto-reply as a confirmation to the user. That auto-reply is killed off prior to arriving by VZW. I am aware of the reason for the block to try and limit spam, is there any way to enable / allow an exception for specific inbound messages?
Support said all is well and it has to be something outside of VZW control, even though the NDR I receive on the mail server states it was dropped on the receiving side.