Uploading a 352.1 MB World to Realms

Yes there maybe people that might be having the same issue or similar but I am trying to upload a 352.1 MB World that was once a Realm back to Realms and it goes all the way to the very end of 352.1 and then throws an error message. Which is infuriating to watch not once but three time (you know just in case it might work). Please tell me there is a fix as people depend on my Realm to have fun as well as I.