isp blocking service error code 202 still!

[Paulie Walnuts]

Before anyone highlights this.. I do realise that there have been a few posts about this issue before which have been marked as solved but I don't think being told to switch everything off and on again is good enough! 

I have had my TV for a few years and have had no issues with connections. However this weekend my power tripped and when it came back on the TV will no longer access any streaming apps such as YouTube, Amazon prime etc. It seems to have decided it has a problem with the network connection even though nothing has changed. 

I have read the previous solutions however none of it works. The firmware is up to date, I have tried all the power cycling and dns suggestions. 

Does anyone know the actual reason this happens? It's a bit of a joke looking on this community that it has been happening for years and still there's no obvious or clear fix. 

Any ideas? 

Thanks 

[Paulie Walnuts]

As an addition to the above. I have two Samsung TVs and the problem is the same with both TVs. Every other device in my home is connecting fine so it's obviously a Samsung problem. 

I have tried restarting the router many times and still it won't work. Might be the last Samsung TVs I ever buy. 

[cwachs]

I've read all of these posts regarding error 202. I am also a network engineer and very well versed in networking. There are 4 Samsung smart TVs in the house. On the same day, three of the 4 stopped working and give this 202 error. The only app that still works on the TV is Netflix, the rest timeout in various ways.

I have changed DNS, I have manually input IP addressing, I have tested on IPv4 only, IPv6 only, dual stack configuration. Same 202 error every time. I've power cycled everything and factory reset TVs. I've changed routers. I've turned off all firewalls. I've tested all TVs on Ethernet and house WiFi. Same issue each time.

Nothing else in the house has any connectivity issues.

But, what gets me is if I put my cell phone in hotspot mode and connect the TV to my phone, the error goes away and everything works. I go back on AT&T fiber connection and the error returns.

So, it only fails when connected to AT&T fiber at the house. AT&T obviously say there is no issue since everything they can test works. Modem was swapped out just in case. Modem (Nokia fiber ONT) was put in router mode. Fails. Modem was put in passthrough mode and my Mikrotik router handled all routing. Fails. Firewalls verified off on modem and router.

If it really was a global AT&T fiber issue, way more AT&T subscribers would be crying out. And, one TV in the house with the same exact setup but slightly older works perfectly. So, how can I blame AT&T when one TV works and another with identical settings does not?

[cwachs]

Found the issue, after 2 weeks and two tech visits. AT&T fiber is hijacking DNS requests upstream of our house. No matter what DNS server is used on the router or the device, that DNS request is hijacked and sent to an AT&T DNS server which is apparently not working correctly.

I configured my home router to use DNS over HTTPS (DoH) and that prevents AT&T from doing their crappy middle man attack on my DNS and now, everything works great again!