Symptoms

On March 1, OneDrive backup failed with on of these errors:

"Error authenticating with resource"

"A configuration error: 'Microsoft OneDrive is not available"

"Service 'Microsoft OneDrive' is temporarily not available"

"Microsoft OneDrive is not available: Error: 400 GET {\"error\":{\"code\":\"AuthenticationError\",\"message\":\"Error authenticating with resource\"

Cause

There was an outage on Microsoft side on March 1, from 8 AM GMT to 9:10 AM GMT.

Solution

The issue was resolved by Microsoft; all backups are running now.