Apple devices "need to connect to wifi network to download update"

Soo.. All of my apple devices are connected to my wifi. I turn cellular data off and I am still able to surf the internet and use apps like netflix and check my mail, etc, etc... But when I go to update the devices, the download and install button is greyed out. Below it, it tells me you need to connect to the wifi network to download the update? I've called xfinity about 10 times, I've restarted the modem 100 times, "forgot" the wifi network on the devices and reconnect. Even went so far as to factory restore my iphone and the issue still persists. I'm out of ideas.

I'm putting this in the iphone topic because we have 3 phones and only a ipod and ipad with the issue.