Storage Accounts are encrypted by default with Microsoft-managed keys. This check ensures that the default encryption is not changed or interfered with.
For remediating from the Azure Portal
- Goto Storage Accounts.
- Select the storage account you want to remediate
- Click Encryption.
- Set type to Customer-managed keys.
- Use option Select from the key vault or Enter key URI to set up encryption with your customer key.
- Save the setting before exit
You can read more about data encryption in Azure here.
https://docs.microsoft.com/en-us/azure/storage/common/storage-service-encryption