I open that game, and navigate to Realms. At this point, I can switch and join my Realm without issue. Then, I try to upload a world from my /saves folder. At this point, the world will upload sometimes partially, but usually completely before giving the error message in the title; Upload Failed! (-1). I get the error regardless of the world, it has done it consistently on almost every world I've tried. After this error, I have trouble getting my Realm to do anything. Joining, switching worlds, and closing the Realm refuse to work for about a half an hour to an hour.