I decided to swap my home internet from Spectrum to WOWWAY, two local cable providers in my area. I own my modem, so I wanted to keep it with the new service. When the tech swapped the service, the modem would not connect. Turns out that Spectrum uses IPv6 on the WAN side, one of the few providers I have heard of that actually does. WOW still uses IPv4 for their connection, which brings me to my point. (If you have gotten this far, and think “what the heck is IPv6 or IPv4”, you are probably in the majority. You might as well read the rest & just enjoy it.)
My understanding is that WOW has been telling customers that their modem will not work after being on Spectrum’s network. As this may be true for some models, I found that I was able to factory reset my modem, and then it would work with WOW’s network. My modem did not have a reset button on the outside of the unit as most network devices do, so I had to unplug all cables from the back of the modem, then plug a network cable into my laptop and power on the modem. The modem assigned me an IP address, which then allowed me to connect to the Web GUI of the modem via its IP address. From within the GUI, I reset the device to factory defaults.
Note: Power-cycling the modem is not enough to make it work. From what I read, the IPv6 is a firmware update that Spectrum pushes out.