DNS NO PROBE NO INTERNET - Time Warner Internet

This question is about "DNS NO PROBE NO INTERNET", with Time Warner Cable internet and apps. I just set up my grandmother's spectrum internet last week using my old Netgear AC1900 WiFi Cable Modem Router Model C700. It says it's connected to the internet and Spectrum also says it's connected. But as soon as I try to load any page, I get DNS NO PROBE NO INTERNET on my Chrome browser both on my Mac laptop and Windows 7 laptop. She has a Verizon ONT landline. I'm wondering if that's affecting my internet and if I need a technician to come and add another cable line. The apartment's previous tenant had Spectrum so I thought it would be simple to just set up.

Or do I have to manually change the DNS for my modem?

Any help would be great, thank you!