PS5 Network Blocked by Routing / DNS Host Name Error

Hello,

I am experiencing a persistent routing issue on my home network where my PlayStation 5 is being blocked from maintaining a connection to the PlayStation Network servers.
The console connects to the internet perfectly, but PlayStation services (Store, Friends List, Online Status) fail to load, giving me Sony's CE-112908-1 error. When I try to load the server status page on the console, it gives me a blank screen with ERROR: 0x00000006 and Couldn't resolve host name.

I am connected via Ethernet and have also tried switching to WiFi.

I don’t understand as this issue was not occurring for the first couple of months we’ve lived here, and now suddenly is an issue.

Here is what I have already tested to isolate the issue to the network/router:

– I connected the PS5 to a mobile cellular hotspot, and it worked perfectly, confirming the console hardware is fine and the issue is strictly with the Xfinity network.

– I manually changed the DNS to public servers (8.8.8.8) on the console, which did not bypass the block.

– I lowered the MTU size, which did not permanently fix the issue.

– If I run a "Test Internet Connection" on the console, it temporarily forces a handshake and works for a few minutes before dropping the DNS resolution again.

– I’ve checked that advanced security is disabled so it is not blocking my PS5

– I’ve restarted router multiple times

– I’ve deleted my WiFi connection, deleted my LAN Port connection, reconfigured, been fine for an hour or so, then back to this issue

Perhaps there is a packet fragmentation/IPv6 conflict with my gateway. Can an advanced technician please look at my routing or check if my console's MAC address is being blocked by a firewall?

Thank you for your help.