Same situation here. Called both Disney Plus and Samsung. Turns out there was a Samsung Smart Hub update rolled out in the northeast in early Feb 2020, and no accompanying Disney + app update to account for the Smart Hub change. D+ did release software on Feb 17, but it didn't seem to do the trick, or it wasn't pushed out to the northeast just yet.
I asked Samsung to roll my Smart Hub version back, was told they couldn't do it. Between this, and the fact that we can't uninstall and reinstall the app, it looks like we're stuck waiting for D+ to push an update that's compatible with the new Samsung Smart Hub. I'm sure our kids will understand...
I am having the same experience. I also belive that when companies put out software updates that break things and they are made aware of it then it is not up to us talk to the app providers but it is up up to samsung to talk with disney+ and resolve the issue. These are apps that samsung provides through smarthub and they should work or be fixed. I shouldn't have to research and spend hours researching something that is your responsibility. If you are working on it then an update on when it will be repaired would be appreciated.
I had the same problem that could be fixed for one day only by resetting as others have described (which signs you out of all apps, etc.). Then the next day we would get the same error code.
I chatted with Samsung today after struggling with this for 2 months and WE RESOLVED THE ISSUE! Here is what they had me do that worked on the first try and they said that this would not need to be changed again.
They had me change the DNS number manually. Please press Menu>> Network >> Network status >> IP settings on the TV remote and manually assign the DNS server value to 18.104.22.168 and unplug and re-plug the TV power after changing the DNS value to apply changes.
I hope this helps you all as well.