Cannot find target smtp address using 'X500:/o=CompanyExchange./ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=Test Account' (4308794)

Probable causes include:

1. The X500 address in question has not been migrated to the cloud. 

2. The source or target (on-premise) mailbox (if any) is hidden from the Global Address List.

3. EWS can't resolve X500 address to SMTP address when connecting to Office 365 for unknown reason.

4. The accounts in question have one or more accounts in the cloud and the Primary SMTP isn't associated with the account that was matched in DMA.

1. For Hybrid migrations to work you will need to utilize the copyTargetAddress.xml with the Sync tool.  This will copy the appropriate X500 to the onprem target, which will then copy it to the cloud via ADConnect or similar tool. 

2. Unhide the source and target mailboxes from the Global Address List and resynchronize mailboxes with Migration Manager DSA and AAD Connect.

3. EWS name resolution can be troubleshot with EWSEditor as follows:

a) Connect to the target mailbox with EWSEditor (please see https://support.quest.com/migration-manager-for-exchange/kb/227651/test-connectivity-and-permissions-using-ewseditor-227651- for details).

b) When connected to a mailbox go to Tools | Resolve Name

c) In the Resolve Name window paste an X500 address mentioned in the log file to 'Enter smtp, name, etc, to resolve' field and click OK.

If EWSEditor can't resolve the name, please make sure the target on-premise mailbox (if exists) is not hidden from GAL (as in point 2.) and if it isn't, contact Microsoft regarding the issue.

4. Break the matching for the user in DMA with the Break Matching task and then run a Match Objects task. Do not just run the Match Objects task with the Break existing matching option but rather run the 2 tasks separately - Break Matching and then Match Objects