Looks like there's no internet connectivity

I set up Open DNS a while back and it was working great. It recently stopped working and when I run the updater I get "Looks like there's no internet activity".

The DNS server settings on the router had switched back to "set up ISP". I've switched them back to the open DNS servers, flushed the DNS cache but has not fixed the problem. What else can I try?

The router is a ZTE268A running windows 10

Just to add, the main reason I'm using Open DNS is stop Samsung pushing ads to the menu bar of my TV. The TV DNS settings switched back to get automatically. I've set them back to the Open DNS serves and I'm not seeing the ads.

When I check network settings on the TV, it says "connect to the network but with no internet". But it is able to access internet content.

Also, I have interent on the PC and the samsung ad sited appear to be blocked.

Does this indicate Open DNS is actually working and I should ignore the error message in the updater on the PC?