This problem occurs if you have fully used your online storage or if you do not have enough space for your online backups. 
You can either,

• Upgrade to the next higher plan to get more storage. Visit the Norton website to know more about the features and benefits that are offered with our other plans. For assistance, contact Member Services and Support (or) 

• Remove the previously backed-up files and free up some space

You can delete a backup set if it is no longer needed. You cannot delete a backup set if only one backup set is available. However, you can create a new backup set before you delete the old backup set.

Delete backup set from your Norton product

1. Open your Norton device security product.

2. In the My Norton dashboard, next to Cloud Backup, click the drop-down arrow and select Manage Backup Sets.

3. In the Backup Settings window, in the Backup Set drop-down list, select the backup set that you want to delete.

4. Click Delete.

5. In the confirmation window, click Yes.

Delete backup set from your Norton account

1. Sign in to your account.

2. In the My Norton page, under Cloud Backup, click View Backup Sets.

   You can view all the backup sets that are in use.

3. Click the trash icon of the backup set that you want to delete.

4. In the Delete Backup Set confirmation window, click Delete > Close.

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