docsis network access enabled denied

 If it's second Even NEW, it could be used, someone bought it, didn't like it returned it, and it got re shrink wrapped. If so the person who originally put it on their account would have to give permission for removal. 

It worked for a year and a half so I doubt it has to do with other people owning it previously assume it wasn’t actually new like it said

No I actually bought it brand new a year and a half ago and it worked fine up until the last week

I’ll be home in a few minutes to check but I don’t believe so

Just got home and no I don’t have those pop ups, my acquire download channel is also at 0 hz unlike yours

Email Cox and ask them to "reprovision" your modem. Also have them check your account for anything from Cox Security. They should be able to see the bad configuration file that is denying you access to the DOCSIS network. Finally, check the contact email you have on file with Cox about anything unusual going on with your account.

Have them verify the MAC ID as well. If something got off in the system, that would cause the issue as well. 

A network security suspension would not cause such an error to be logged in the modem.  The modem would successfully provision and get online but be put in the walled garden.