[Exchange Migration] Local autodiscover for domain.com failed.

This error occurred after moving an on-premise user to Exchange Online / Office 365.

Lets say we have an on-premise user: [email protected] who we then move to our cloud Exchange Online tenant: [email protected].

When we attempt to use autodiscover on the primary email ([email protected]) the autodiscover services goes - 'hmm... looks like we should be looking in the domain.com domain' - whereas really the user now resides on the domain.onmicrosoft.com domain - so we need to specifically instruct or rather associate the mailbox (joe.bloggs) with a remote domain of 'domain.onmicrosoft.com' (this remote domain should be automatically been created when going through the Microsoft Exchange Hybrid Wizard.)

So to associate the mailbox with our Exchange Online domain we issue:

Set-RemoteMailbox -Identity joe.bloggs -RemoteRoutingAddress [email protected]

And then retry the autodiscover process.