Are the sites all on the same host or same server?
I’ve seen this a few times, and it usually seems to be a spam filtering issue, where some combination of the host and the content of the message is causing some. If you have a second email address at a different domain, can you try adding that to the field, so you receive messages in both places? (I usually recommend a yahoo account, since they don’t block as much mail.) If you do receive it at one account and not the other, then your mail provider would be blocking them.
If you know what time a scan completed that should have sent a message, you can ask your host to see if they can see any rejected mail at that time — if you tell them the address the message was going to, that will usually help too.
You can also check the common blacklists here, though in some cases, it may just be aggressive filters based on the message content, even if your server isn’t on these lists:
http://mxtoolbox.com/blacklists.aspx
-Matt R
Thank you for your reply.
The problem seems to be resolved and it was due to problems with our email and filtering as you suggested.
Great, thanks for confirming!
-Matt R
