World not uploading to Realms

I'm on a ps4 and been trying to help my brother upload his 378mb world that we been playing for over a year building to realms and it would get all 378mb but right as it's finishing, it'll say an error has occurred and it's getting frustrated. He is using his free trial of realms so he can put his world on it so I can be able to access the world without him having to be on. Please fix this…