OpenDNS working on some computers but not all

check your netgear router's configuration that the dns server is one of opendns's i.e.
208.67.222.222 & 208.67.220.220 ?

You might also have static DNS entries on those computers

tried both of those options already - computers set to obtain DNS from the router and the router is set to both settings in David's post.  Tried all solutions in the link I posted above - still no luck.  Makes no sense - was working great a few days ago...

Have you check for malware that is redirecting your traffic

Thanks Natty - Malwarebytes (paid version) says I'm free of everything.  Keep the ideas coming - I'm game for anything!!

on each of the offending computers what happens if you do an ipconfig /all ? What dns addresses are you getting?

The devices that successfully block are iPads and iPhones - the offending computers are traditional PC's / Laptops connected to the home network via wired or wireless.  I tried "ipconfig /allcompartments /all" on each offending PC and get the DNS as 192.168.1.1 - which is my router.   The router is correctly pointing to 208.67.222.222 (see screenshot) .  Malwarebytes on each computer shows no Malware.

I know the router / OpenDNS is configured correctly because I get the OpenDNS blocking screen on my tablets - the same offending URL on my desktops / laptops all go through.  It's got to be something on the PC but it just doesn't make sense.  About to buy a new router I think to see if maybe that fixes the problem (I'm desperate).
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