Hi Rod,
thanks for the breakdown. However - tried all the above.
I've been working with coding for donkeys years now - and have countless other packages all running fine on the server. Some quite complex like Moodle, some as simple as instant downloads for audiobooks, and a couple of ecommerce sites. any number of mailers, like news letter subscriptions etc etc.

phpinfo tells me that the linux server is running sendmail. In addition to this, the webmail side, that I don't use, uses qmail.

all those email addresses you see are valid and belong to my domains, hosted on this same server.

Well. Only recently taken up zen-cart - and what do you know. the core of the product - the email system - is a real dog.
I've wandered across the forums, and the internet looking for answers, and as usual .... nada. although there are many many people having email problems. So I'm not alone.

All of the above options I tried, were to see just what would work and what wouldn't. As it turns out - nothing works. In that I still haven't received even one email from the system. Oh sorry. My son tried a purchase on the audiobook site I ran up, and he got a text message back as an Order Confirmation. That's the only email I've ever seen from both systems. I thought the audiobooks one was working but it's not after all - only that order confirmation.
So of all the software I have installed - only zen-cart wont deal with email properly. So I can say with confidence that it's not the ISP/Hosting service or server. It's not anything else but zen-cart as far as I can see.

the email-archive addon tells me that email has been sent from the various tests - but there's no sign of it. So I need to go deeper it seems.

so it looks like I'm going to have to delve into the code and try and see what is happening. what a pain. A real pain.

Thanks for your thoughts on the subject Rod. All input is very welcome in case I miss something - as I'm sure I will :-)

cheers
Robert