I have an Arris TM1602 and a Sagemcom Fast 5260 both are leased from Spectrum formerly Time Warner Cable. I have tried rebooting the modem and router to no avail.
Nothing unusual about that, since the Arris TM1602 is an EMTA telephone modem that does not support IPv6 on its data port. The unusual part is that you had it working before the power cycled.
Spectrum knows there's an issue and is providing business class customers with seperate emta phone only modems then an Ipv6 Ubee combo modem router with wireless.. No all in ones , the emta phone will not work with IPv6 and it shoots down the IPv4 as well in those.
I do not have phone service with Spectrum anymore, I am using Vonage now. Should I exchange my modem for an internet only modem? I had a second power outage which restoed my IPV6 address.
Spectrum should have provided you with a replacement internet-only modem when you cancelled your phone service with them. You should have better luck with a new one that officially supports IPv6.
But from recent experience, don't try to run both traditional IPv4 and the new IPv6 protocols through the same modem at the same time. I'm running a Zoom 5341J and SO's iMac with IPv6 crashes regularly and often reboots while I'm doing file transfers on my Windows 10 machines with IPv6 disabled. My Android phone on WiFi doesn't seem to care though.