O365 - How to add a mail.onmicrosoft.com smtp address using PowerShell

ben@byteben.com (Ben Whitmore) — Sat, 28 Jul 2018 00:00:00 +0000

So you are on-boarding user mailboxes to Exchange Online and your user does not have a .mail.onmicrosoft.com smtp address. STOP. Your mailbox migration will fail without it. (Maybe you know this and this is why you are here :) )

Exchange-Address-Book-Policy - Tag - byteben

O365 - How to add a mail.onmicrosoft.com smtp address using PowerShell