Earlier this week, António Vargas wrote a post on his blog about this SMTP error message he encountered while using MigrationWiz:
Your migration failed checking source credentials. The SMTP address has no mailbox associated with it. Error: ErrorNonExistentMailbox Detail: SmtpAddress firstname.lastname@example.org
When you take a look on our community site, you will find that this error is usually generated when either the source or destination target does not exist. António went even further with this, and was so kind as to provide an explanation.
It turned out that the MigrationWiz EWS (Exchange Web Servers) queries will fail if the mailbox is hidden from the Global Address List. When the mailbox is hidden from the GAL, he above error message will be thrown during the migration. To solve this issue, António correctly says to disable the "hide from Global Address List" option on the mailbox you're migrating.
Read the full article here. It's worth a look! Thank you António!
For more information on MigrationWiz tips and tricks, please visit our Knowledge Base.