After changing the Migration Manager for Exchange service account password and following all steps in Article 16130, entering the updated credentials in the associated DAG properties fails with an Access is denied error. The EMWMigration.log may show something similar to the following:
1/1/2018 12:41:06 PM:152 MMExCore|Quest.MigrationManager.Exchange.Core.NetUtils+<>c__DisplayClass1.<CheckCredentialsOnServer>b__0 Error: The account 'domain\DMMaccount' you specified for access to DAGname are incorrect. Please specify the correct user name and password. Details : Access denied
2/12/2015 12:41:26 PM aeEMWGUIWizards::frmProperties::cmdModifyWinCredentials_Click Credentials are invalid. Server: DAGname. Username: domain\DMMaccount.