If a backup fails, the usual causes are disk space and folder permissions on your server.
Disk full
Backups are saved in wp-content/uploads/coworkmcp-backups/. Check disk usage in your hosting control panel. To free space, empty the WordPress trash (posts, pages, media) and remove large unused media. Only the newest 5 backups are kept, so old ones clear themselves.
Permission error
WordPress must be able to write to wp-content/uploads/. If your host has locked that folder, ask them to make it writable by WordPress, the same permission it needs for uploading images.
Still failing?
Ask Claude “Show me the PHP error log” and include what it says in a support ticket.