Unable to upload new worlds in Realms

I'm pretty sure there's nothing wrong with connecting to the internet, but when I try to upload a new realms world to replace it, I get an error and it doesn't succeed. .. Also, I tried to replace the world that I was able to enter the server with another world, and after the error occurred, I could not enter anymore. I just put it in easily.
Originally, it seems that it was restored so that it can be put in the uploaded world, but I think that it can not be put in the newly uploaded world. Please repair it.