I don't know if i have been lucky today, but so far i haven't seen the message pop up on my TV screen during watching the Sports channels.Perhaps it was an ISP or Now TV issue, as I've changed nothing here.
I've also started getting this error on my Now TV stick recently. As far as I know there's been no change apart from a software update dated Aug 21 (that changed the UI quite a bit).If it is the software update I hope it's resolved soon.