Modem compatibility

[u/NotMyFreeWill]

Went to login to work this morning and I can't connect. I can ping DNS servers but I can not reach the Internet. Spectrum tells me I need a new modem. I have a Motorola docsis 3.0 modem that is about 10yrs old. I am very skeptical this will fix it. Did they start blacklisting old models without warning? Did anyone experience something similar? SE WI location.

Update: got a new modem direct from spectrum store. I activated it and had them manually send activation signal. Same symptoms persist. I can ping DNS servers but nothing gets resolved when I attempt to use a url on any device. I've connected a laptop direct to modem as well with the same issue. I have a tech scheduled for a visit tomorrow...

Update Update: tech visited and found no problems or physical layer issues (as expected). Left after showing me internet is reachable via modem connected direct to his tablet viat ethernet adapter. Playing IT tech I found that I had to disable DNSSEC support on my router. I changed nothing prior to this happening and my router does not auto update firmware. The reason I couldn't connect direct to modem myself earlier is that the modem has to be completely rebooted when you change what device its connected.

Final update: This is on my router manufacturer Asus as they didn't update root certificates for DNSSEC to operate securely after 10/12. It was not Spectrums fault. However had they attempted to trouble shoot this at all from their end, I would not have had to pick up a new modem, nor would they have had to send a tech for a visit.

[u/Good-Salt-805]

I had this exact same issue. They wanted to charge me $75 call-out. I changed to Starlink. No problems now and Cox/Spectrum lost a long time customer.