I've got a weird one here. We have an LZ980 OLED, about a year old, which has started having issues with certain apps when connected to the main network. We noticed it with TVNZ+ a few months ago, but now have the same issue with Netflix, ThreeNow and Disney+. Amazon Prime Video, Youtube and Sky Sport Now (the freebie subscription with the set) are fine.

What happens is - TVNZ+ will timeout when it normally play an ad, Netflix will stop playback about 2 minutes in to any programme, Disney+ and ThreeNow just time out.

I'm running an expired (ssh don't tell my WatchGuard account manager) WatchGuard Firebox T70 with 12.7 firmware, connection is 2degrees gigabit with static IP. The TV is on our home VLAN through a Netgear GS116E "plus" switch. I am not sure if the issue was before I split the home and home office into separate VLANs.

The strange thing is that these apps all work without issue if I hotspot on to my phone (Note 20 Ultra), and the TVNZ+ app (haven't tried the others) works fine on my Xbox Series X, which is also on the home VLAN.

DNS was 1.1.1.1, have set to 2degrees new forwarders 111.69.69.69 and 111.69.69.68 (the TV only takes one at a time so I've done them one by one) and also set up DNS forwarding on the Firebox to the 2degrees ones and used that. The WatchGuard has a TCP-UDP rule to allow any traffic from the reserved address for the TV, and I've also tried an "any" rule. I have also tried on wireless (Unifi AC Lite) but get the same issue.

Packet capture shows that TVNZ is making a bunch of DNS requests and getting what appers to be valid replies. I can't help thinking it is somehow DNS related though, as it's not just making one or two - it makes multiple requests in a row in the Firebox logging, and the capture shows it's making the same request multiple times.

Wondering if anyone else has seen a similar issue? I could try a back channel to WatchGuard but really prefer to use those kinds of favour more for client issues, and could try another router but that's an awful lot of messing around with the setup I have with an IKEv2 VPN back to work etc.