While I don't know much about networks, I'm a website developer so know a lot about debugging. And after a lot of debugging, I'm completely stumped, and am hoping somewhere can connect the dots for me.

I have an LG smart TV connected via wifi. On it, I can watch Netflix + YouTube absolutely perfectly. Freeview on demand / TVNZ on demand used to work perfectly too.. until one day, they didn't. I'm focusing my debugging on the freeview on demand app.

The app loads the list of shows perfectly fine. I select one.. it displays the channel logo, and then sits there. After a couple of minutes, the screen goes black. If I leave it on the black screen for around 5-10 minutes, it eventually starts playing. Replicable every time, though some shows (it seems those without ads) load slightly quicker - but still 2-5 minutes when it should be instant.

I've done all of the usual steps, going as far as full factory resets of both the TV and router. No change. The app developers can find nothing wrong.

I discovered that I could set up my laptop as a mobile hotspot, and then use Wireshark to inspect the packets being sent through. I wasn't expecting much, given https:// requests are encrypted, but I held out a faint hope there would be some sign of what it was trying to do during those endless minutes of black screen.

But here's the kicker. When my TV is connected to my laptop's mobile hotspot.. suddenly everything works perfectly! Shows load and stream within a couple of seconds. Change back to a direct connection to my router.. and it's broken again.

Signal strength? It seems not; other than the fact Netflix streams without issue, I tried moving my laptop to the opposite end of the house and it still works perfectly, while the router is in the same room as the TV (just too far away to be wired).

It's as if my router is specifically seeing the TV device doing something it doesn't like, and blocking it for a fixed period of time. But I've checked through all of the settings in the router and can't see anything applicable; and if it used to work but doesn't despite a factory reset.. ? And wouldn't the same packets come through from the hotspot anyway?

I am so confused. If anybody has any recommendations of where to go from hear, I've love to hear them.

Specifics if it helps:

- [LG] webOS TV LJ550T

- NetComm Wireless NF4V (with fibre connection)

- can provide other details if you let me know what's relevant