When running Migrate User Data and Mail Box Enable Existing AD accounts, Mailboxes do not get created and you receive error 7429-1-22-00000000.
NME by default will look for a proxyAddress attribute containing proxyAddresses provisioned by Microsoft Transporter. If contacts were not provisioned in this way then the proxyAddress attributes may not be available when NME searches AD before removing the contacts and Mail-Box enabling the AD User.
Selecting that contacts were provisioned by Other or SMTP during the Migrate Mail Data Wizard should set the two parameters that effect this behavior to 0.
These parameters are:
Check the value of these settings in the migration logs and if necessary set them values manually to resolve this problem.
Please see the NME Parameters Reference Guide included with the product for more information before applying these parameters.