Last week I exchanged the SMC gateway for a Cisco DPC 3825 at the request of Shaw. The Cisco is running with the exception that no device on the network, either plugged directly into the gateway or on WiFi will send e-mail on iCloud: not either iMac, not one Android phone or Android tablet, not BlackBerry, not Apple Macbook Pro. The machines all receive mail and send on other servers such as Shaw and gMail. I have looked on the Support pages and the only thing I can see is that it is either a problem with Spam being sent from one of the computers on the LAN, error messages triggering spam filter, or needing to reset passwords.
I have not reset all the passwords because the problem is on multiple iCloud accounts on multiple devices and I think it is something else.
The problem occurred immediately the Cisco gateway was on.
If anyone has an idea, I would be grateful as the whole house is on my case and I am having to send on gMail all the time and everyone else has to work around it somehow. The only way iCloud works on my BlackBerry or tablet is if I am on the cellphone network instead of the WiFi or Ethernet through the gateway. It has to be the gateway. Every other feature works on the gateway.