It's happening for me too.
Ok, thank you! 😃
The name is just "New World".(however, no other world has that name in the singleplayer list).
I was also unable to reproduce the problem. Could it be an issue with another world in my list? I had a desert world that I deleted before starting this one.
Approximate Coordinates:
X: 7
Z: 198
It's all good, I can access my Realms again!