I'm having issues with XB6, I used have own modem and changed it last week to XB6 and since then many devices don't work.
Note 9 Many pages says "Page cannot be reached"
Playstation dont even connect with error DNS error has occurred.
iPhone 8 dont open many apps such as MS teams or Outlook.
iPhone XR having also same issues.
I even cant open xFi App when its connected to the XB6 becasue of DNS server. If I connect to XfinityWifi it will work with no issues.
I suspect the following:
If you have any security apps installed on any of them, or DNS redirect apps like OpenDNS or Cloudlfare in your LAN, they should be uniinstalled or otherwise reset to defaults.
If you can access xFI on the app or at https://internet.xfinity.com, try disabling xFi Advanced Security temporarily and see if it solves the problem.
Thanks for the answer, I have advance feature disabeled.
I called Comcast yesterday and the did something which made it work.
And today all same issues. Even my mobile voice mail app cant sync and Playstation same thing.