Can't replace Realm with backup

As stated in the title, I can't get my realm replaced with a backup. The backup is there and I downloaded it. I press the backup, currently '30m ago', and I selected 'Replace Realm With Backup'. After a little wait, a Minecraft notification comes up saying that 'replacing the world with the selected backup failed'. I have tried this many times, and I am on high-speed two bar WiFi.

 

Thanks a ton,

John