Manual Mailbox Switching Fails with an Autodiscover error - Unauthorized (401) (4278018)

Manual Mailbox Switching Fails with an Autodiscover error - Unauthorized (401)

When using Migration Manager for Exchange 8.13 and manually switching a mailbox, you receive an error regarding Unauthorized (401) for Autodiscover. Both the Source and Target Exchange environments are using the same primary SMTP address.

Beginning in Migration Manager for Exchange 8.13, the Migration Agent for Exchange (MAgE) tries to use Exchange Web Services (EWS) for communication to the Source environment by default. Since the Primary SMTP address is the same for both Source and Target, the Source EWS call gets redirected to the Target Exchange. Since the credentials that are passed to Target Exchange are from the Source Domain, Autodiscover responds with an Unauthorized (401) error.

Resolution 1:

Set the appropriate Source Autodiscover URL using the Set-DMMExOrganizationProperties cmdlet.

Resolution 2:

Configure routing to Source Autodiscover from the domain that the MAgE Agent Host resides. Please consult Microsoft for appropriate routing support.

Resolution 3:

Set the UseEwsProtocolForSourceIfAvailable parameter to $False using the Set-DMMExProjectOptions cmdlet.