We have a similar issue. Amazon streaming app worked great yesterday. On latest firmware/apps updates etc then all of a sudden Amazon app can't connect.
The TV is a UE46F8500.
Saving grace was our Samsung BD7500 bleary smart hub was working so continued streaming from that until that stopped today.
Called Samsung today, reset Smarthub, reset TV settings now all the apps have gone aside the Samsung Web Browser. Went into 'more apps' and selected Amazon/Netflix and re-added them and when returning to Smart Hub Apps window they are there until I exit the smart hub and re-enter and then they have disappeared again.
Was on the phone for 30+ minutes with Samsung. They did remote connect, checked IP/DNS/SW versions and said they would get back to me. Called me back 10 minutes later to say the 'servers' were being maintained.
If they have been hacked as you say...could be without Smart Hub for quite some time!
Plugged in Apple TV and it doesn't have Amazon as an app! Aargh. Now using Samsung laptop plunged into TV......
Why do I buy Samsung?
My smart hub apps self deleted due to Amazon indicating I needed an update. Samsung found no update needed, however it proceeded to self delete all my apps it counted down from 18. No cancel or back out function allowed. All the apps were successfully deleted. Calling Samsung got me to we are very busy with high call volumes. We tried to do remote assist repair, they answered, said all is normal to delete all the apps but they connected us to the folk that would fix the tv. It was the same message to wait forever. We transferred to USA help number the help person had us reset apps and double check internet connect. No apps would loa just got a message in the app area of screen how we coul connect to the world. BS.
TV is model number with extra customer service extension is PN60E550 D1FXA.
Seems like Samsung servers were hacked and they can't reload standard apps like Amazon Netflix or Hulu. System says the Internet is working but when you use the web or other apps they all fail due to network not connected. Seems like the update actually broke the smart hub and they can not say when they can even call back to check with us to fix the smart hub. Some there shoul ship a recovery thumb drive to recover the basic hub, if that got hacked to oblivion.

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