I have been experiencing this exact issue as well.
My son and I have an existing world that was created on the Switch. We set up a Realm and generated a random world and everything worked as expected. When I tried uploading the world we had been playing in locally (nothing fancy or beyond the default settings) we see the same behavior as above. On the Switch, if we try to join the realm it starts to load, then for a few moments the screen cuts back to the panning background that is typically beyond the menus, then I we get an error that we are unable to connect to server.
If I connect to the realm from an iOS device, I'm able to connect normally and everything is find until the user on the switch tries to connect. Oddly, while the Switch is starting to load the world, the user's character pops up in the world, but then when the error pops up both users are disconnected and I am unable to reconnect until the error is cleared.
I've also tried downloading a copy of the realm from the server. That appears to work, but if I try to load it either on the Switch or an iOS device I get the "A newer version of this game has saved this level." error. Both Switch and iOS device seem to be running the most recent version available (1.10.0)...
Will Slusher
I have been experiencing this exact issue as well.
My son and I have an existing world that was created on the Switch. We set up a Realm and generated a random world and everything worked as expected. When I tried uploading the world we had been playing in locally (nothing fancy or beyond the default settings) we see the same behavior as above. On the Switch, if we try to join the realm it starts to load, then for a few moments the screen cuts back to the panning background that is typically beyond the menus, then I we get an error that we are unable to connect to server.
If I connect to the realm from an iOS device, I'm able to connect normally and everything is find until the user on the switch tries to connect. Oddly, while the Switch is starting to load the world, the user's character pops up in the world, but then when the error pops up both users are disconnected and I am unable to reconnect until the error is cleared.
I've also tried downloading a copy of the realm from the server. That appears to work, but if I try to load it either on the Switch or an iOS device I get the "A newer version of this game has saved this level." error. Both Switch and iOS device seem to be running the most recent version available (1.10.0)...