There are several reasons why a daily backup may not run. Please check the following:

• Scheduled Backup time: The backup may be set to run later in the day. You can check when the Auto Backup will next run by opening the VPS Auto Backup tab in the Customer Control Panel here. In the column "Schedule of next Backup" you should see when the Auto Backup will run next.
• Auto Backup status: If the Auto Backup has been set to inactive, no backups will be performed. You can check that the Auto Backup Add-On is enabled on your VPS  by opening the VPS Auto Backup tab in the Customer Control Panel here. In the column "Backup Status" you should see if the Auto Backup has been enabled for your VPS.
• Backup age: If the backup is older than 10 days, it will be automatically deleted so you will not be able to access it.

If you've checked all of the above possibilities, you can reach out to our customer support team to look into this further. 

You can raise a ticket with the customer support team via the Customer Control Panel here.