The following error may be logged in the Office 365 module log file when working with the Office 365 Leavers functionality in Archive Shuttle:
2015-11-27 15:32:14Z|3264| 16| INFO| ExecuteInternal|Provisioning Mailbox for [David_Smith_leaver@somedomain.onmicrosoft.com] Create archive [True]
2015-11-27 15:32:18Z|3264| 16|ERROR| ProcessPipeErrors|Errors were detected. Review the following:
2015-11-27 15:32:18Z|3264| 16|ERROR| ProcessPipeErrors|System.Management.Automation.RemoteException: You can't use the domain because it's not an accepted domain for your organization.
Check that the domain which is configured on the Office 365 Environment page is spelled correctly and that it is a domain, which the O365 organization is responsible for.