If the OPC cannot remove a backup it will give an error with the details:

This can be caused if the permissions have been changed on the backup directory, or if you have set a custom directory that does not have the correct permissions.

To check and reset the permissions for the instance backup directory open the support menu from the left sidebar and click the “Run Migrations” button.

This will run a number of checks on the OPC’s installation and will update the backup directory permissions to what is needed by the OPC.

Once finished you will then be able to manage your instance backups via the Web GUI.