Samsung TV Won't Connect to Netflix After Being Turned Off

I have two Samsung TVs, a UE55JU6500 and also a UE48JU6400 and I have the same problem on both of them.
When I turn on the TV and try to connect to Netflix, it fails and comes up with various error codes (which don't see to relate to the issue).
To get Netflix to work I have to reset the Samsung Smart Hub software and re-enter the Smart Hub details, e.g. confirm wireless AP, remote control settings. Then I open the Netflix app and when it fails, I reset the Netflix app and then enter the username and password....and then Netflix works again....until I turn the TV off again (by this I mean on standby, not powered off).
When it fails I check the Netflix status, and it can always connect to all 3 Netflix servers and I tried changing the DNS settings to 8.8.8.8 too...but this made no difference.
This happens on wireless and on wired, so it does not appear to be linked to this.
The problem is identical on both the UE55JU6500 and also a the UE48JU6400 TV.
I have to do this every time I watch Netflix on a Samsung TV. So I normally end up watching Netflix through my Nintendo Wii or my Samsung Galaxy phone neither of which ever have this problem.
Samsung blamed my firewall settings and the http port 80 was not permitted, but this is completely incorrect. The setting are completely fine.
Samsung also got me to do the 'up up down down left right left right up up up up' process using the remote control. This made no difference to either TV, the problem continues.
I also made sure the TVs were directly connected via wireless or wire to the broadband router. This made no difference. Wired, wireless, direct or indirect the problem is always the same when using either of the two Samsung TVs.....and again my Samsung phone, iPhone, Nintendo Wii, Apple Mac, etc never, ever have a problem.