Mailbox Move step fails with error 'Object reference not set to an instance of an object'

Overview

The mailbox move step fails with the error below:

Execute_HYBRID_MoveMailboxToO365: An error occurred during Exchange Online Powershell | Object reference not set to an instance of an object. | Result: Not received [ProcessResult]

Cause

For this specific instance, the customer was unable to process any mailbox moves within their M365 tenant even when they tried internally. 

Solution

The customer will need to resolve the issue and then those failed moves can be restarted.