You are now in the Help section, which is the best place to get help. I don't remember where your thread was before.
This still sounds like a server problem to me, and I can't really help with that. The iPad isn't going to send you ADMIN messages. They come from either your server, or the server that the email was sent to. There are various reasons why you might get an ADMIN message. Without reading the message myself I can't make any kind of guess.
Since the message will contain private email addresses and other identifiable information I do not recommend you post it here. You'll need someone who you trust, and knows a bit about email and the internet to help you. Or talk directly to your internet and/or email provider. Sorry.