> However, there's no correction process for Spectrum's DNS sinkhole

> But back to the topic: someone mentioned to me that Spectrum may not be the direct providers for the DNS services they provide to their customers. If anyone knows anything about how I might discover and reach out to the people responsible, please let me know.

I suspect what’s happened is an incorrect assumption that DNS is even the issue here. Because you mentioned Spectrum Shield, I suspect it is not.

Spectrum Shield (https://www.spectrum.com/resources/internet-wifi/benefits-of-spectrum-security-shield) is a customer-managed security protection service built into their gateways (I assume you can turn it off). The malware and content detection engine behind that is very likely run by CujoAI (https://cujo.com/) and it does not use DNS query/response exchanges as the control mechanism (in part to counter-act DNS-changing malware or malware using its own DoH channel for example).

You should contact Charter/Spectrum to have them investigate what their system might be blocking this content.

Comcast (where I work) runs a similar system (https://www.xfinity.com/support/articles/using-xfinity-xfi-advanced-security) and maintains a site to report these sorts of issues (https://www.xfinity.com/support/articles/report-blocked-website).

Jason