Google Sites backup errors can be caused by a variety of issues. Are you using Google Sites in your Google Apps domain? If so, can you please confirm that Google Sites are enabled in your Google Apps domain and that you have enabled permissions for Spanning to back up your Sites data. To check that Google Sites are enabled for your G Suite Domain, please follow these steps:
1. Log into your Google Admin Console (admin.google.com)
2. Select Apps
3. Select G Suite
4. Confirm that Sites are 'On For Everyone' (see picture below)
To check that Spanning Backup is enabled for your G Suite Domain, please follow these steps:
1. Log into your Google Admin Console (admin.google.com)
2. Select Apps
3. Select Marketplace Apps
4. Select Spanning Backup
5. Confirm that Data Access is 'Granted' (see picture below)
If both Sites and Spanning backup are enabled for your domain, and Sites are still failing to back up, please confirm that the user is the owner or writer of the desired Google Site. The user needs to be the owner or writer of a Site for Spanning to be able to back it up successfully.
If these are both enabled, then it is likely that you aren't using Google Sites in your domain, which is causing Google to return an error when we try to back up your Sites data. To solve this Sites backup error, you have two options:
1. Disable the backup of Google Sites within each of your Spanning user's settings, so that we don't try to back up that data, thus, you won't get this error. Only do this if you don't plan on using Google Sites, and don't want this data backed up.
2. Create a blank tester Google Site and then share the site with all users in your Domain. Since you will now have a Google Site, you won't return this error when trying to back up your Sites data.
Please note that if you are receiving 'partially successful' backup errors for your Google Sites backups (instead of 'Failures'), there are some limitations with the Google Sites API which prevents Spanning from being able to back up everything in your Google Sites. You can read a more detailed description of these Google applied restrictions here:
How is restoring Google Sites different from restoring other data types?
Please contact support if you have any additional questions.