I have recently bought a realm and tried to upload one of my worlds to it on pocket edition. The world was about 40mb and had about 6 mod packs on it. When I tried to upload the world it went through the exporting process, but when it got to the initializing upload part, after about 30 seconds an error window popped up saying "We couldn't confirm if your world uploaded properly. Please join your realm to check, then try again if it hasn't uploaded to the new world." I joined the realm and the upload was unsuccessful, so I tried again. Unsuccessful. I tried to upload a brand new world with nothing added to it and the same thing happened. I tried to reset/close the realm and it wouldn't let me do either of those. This is only an issue on pocket edition.