Backup and Migrate:Azure Backup fails with files path Source and azure blob storage Destination. Fail includes Internet Server 500 error

Problem/Motivation

Backup and Migrate:Azure Quick Backup and Advanced Backup with Files Path Source and Azure Storage Blob Destination fails with Server 500. After a delay, the Server appears to hang on the Backup page.

• Files Path consumes 700MB.
• Backup with Drupal Database Source and Azure Destination works.
• Backup with Files Path Source and Local Storage Destination works.

Please let me know how to prune the Files path and provide further Server information if it will help diagnose or repair the issue. Thanks.

Steps to reproduce

1. Setup Files Path as Source
2. Setup Azure Storage as Destination described on the Backup and Migrate:Azure page
3. Perform a Quick Backup using the Files Path Source and the Azure Destination.