This case is another one of those countless issues which reminds you every day that no matter how long you have been doing migrations you can never rest on an old knowledge and experience. Rather you need to keep learning something new which may at first appear same old, that’s a nature of our job 🙂 Everyone have probably seen MAPI_E_FAILONEPROVIDER mailbox access error thousands of times and knows it may be caused by name resolution, permissions (mostly)… I have also seen some “exotic” cases where same LegacyExchangeDN was present on the proxyAddresses attribute of another recipient (Contact) preventing both Mail Sync Agent access and end user’s Outlook MAPI login. But I bet the one I am about to describe is not something you’d encounter often.
I was recently working on migration from Exchange 2010 to Office 365 using DMM 8.11. I have installed DMM AD/Exchange console on computer1 and had a dedicated agent host computer2 to host my Mage agents.
Another quick article about some new QMM (DMM) MAgE functionalities. When configuring new Calendar or Mail Sync MAgE collection, there is an option to add AD root with particular LDAP filter. It seems that you’ve done it all right,