DirSync no longer works - Email and calendar - Office 365

After we set up the directory synchronisation is worked, now it no longer does. When I manually initiate a sync with Start-OnlineCoexistenceSync I get an error message in the event log:

source: MIIServer
event ID: 6000
description: The management agent "SourceAD" failed to run because the credentials were invalid. Verify the credentials and configuration for the management agent.

When I run the Directory Sync Configuration Wizard, I get the error message "the enterprise administrator credentials that you supplied are not valid." even though I am positive that user name and password are correct (please note that a wrong pasdword would give a different error message) and that the user in question is a member of the enterprise admins group.

For some reason, DirSync is not being able to connect / login into the Domain Controller. If that connection is not possible, then both ConfigWizard or SourceAD manangement agent will fail.

To help isolate the problem here are my suggestions:

1. Verify that DirSync machine can ping the Domain Controller.

2. Verify that you can access/browse the AD from the DirSync machine using the same credentials. You could use some tool as LDP or ADExplorer to do that.

3. Try re running ConfigWizard using another type of account. For instance Domain Admin if possible.

4. Check proxy settings, network connectivity from the DirSync machine.

Please let us know if you still have this issue.

Hello

After you have verifed you can log into something with your enterprise credentials you can manage them from the tool.

SourceAD is the agent which imports objects from the on-premise AD

If you open C:\Program Files\Microsoft Online Directory Sync\miisclient.exe ->Click the management agents button -> Select SourceAD Properties then Configure - you should have a menu to re-enter your credentials.

Thanks

Steven