sorry I wasn't clear
Sorry I wasn't clear in my problem. The Powerstore only ever emails the "Forget Password" information. It will do that every time. But, the Powerstore doesn't ever email the registration information or the order information.
It is not because the SMTP server is refusing to relay to an address because it does email the "Forget Password" information. It does not email the registration information (to the same email address) or the order information. I have checked all the spam filters.