IPv6 Relay Error

I have an Apple Extreme Router with Version 7.6.4

I just got high speed internet access from Brighthouse using Arris router/modem. The Arris router has been turned to Bridge Mode.

Brighthouse tells me they only us IPv4. Can I disable IPv6 on my Airport Extreme?

Or some other option to fix the error?

Using the AirPort Utility, under the Internet tab, it's set to DHCP. If I go under "internet options" then Configure IPv6: Automatically; and IPv6 Mode: Tunnel.

My devices can connect wirelessly and get fast connections. The only issue really is the amber light flashing on my Apple Extreme.

Any help is appreciated.

Thank you,

John