Mac backup failed

Hi,

Just noticed that one of my backups failed, tried force backing up and that failed too, anyone have any ideas?
Operating system Catalina.
Here’s the screenshot of my scheduled backups.

Cheers

What size drive are you backing up too?

Backup will fail if the maximum size of the backups exceed the size of the storage, try manually deleting (through Roon) several of the oldest backups on the storage disc then try forcing another backup. If the backup then works, that’s your issue.