I just updated to the 1.16.21 patch and see the error message frequently like a few others, but now my Realm says that I must update to the most recent patch to play, even though I have already updated to the newest patch.
The issue still remains for me as well, and I have been attempting to upload my world to a realm on a variety of wifi connections for over a month.
I just updated to the 1.16.21 patch and see the error message frequently like a few others, but now my Realm says that I must update to the most recent patch to play, even though I have already updated to the newest patch.