Same exact problem here, started today, never happened before.
- Did a hard factory reset, no luck. So I'm not sure if it's related to an update (I suppose the factory reset should wipe all updates)
- Tried connecting to my cell phone personal hotspot, the same. So the problem is not my router (all other devices work perfectly)
- Tried different DNS servers (including 8.8.8.8), no luck
- Even though TV reports no connection, it anyways logs me in to my Samsung account on SmartHub, but no application can be started
Given that a couple of us started with this symptom today or in the last days, maybe is related to some Samsung service being down?