Storage account should use Private Link Connection

Description:

You can use private endpoints for your Azure Storage accounts to allow clients on a virtual network (VNet) to securely access data over a Private Link. The private endpoint uses an IP address from the VNet address space for your storage account service. Network traffic between the clients on the VNet and the storage account traverses over the VNet and a private link on the Microsoft backbone network, eliminating exposure from the public internet.

Solution/Reference: 

Read more:  https://docs.microsoft.com/en-us/azure/storage/common/storage-private-endpoints