After several attempts have been made, it seems like I am unable to upload a single player world on to Realms. Every time the same error appears after 10%, saying Upload Failed (-1). The cancel/back button also seems glitched. I tried to restart the computer and the game, nothing seems to be helpful. I also tried to upload a brand new regular survival world, same problem occurred.

I can create and join a world on Realm just fine. This issue only happens when I try to upload a single player world.

Is there any solution to this problem? Thank you!