To delete a backup from Plesk we must access our Plesk and go to where we have the backup:

- If we have it in a single subscription, we must go to Subscriptions > click on the subscription > Backup Manager.

- If we have it at the server level, we must go to Tools & Settings > Backup Manager.

To delete it, we have to click on the white box on the left of the backup and click on delete:

Then we click on delete:

And it deletes the backup: