Hey everyone! I'm trying to sync Microsoft 365 with our on-premises Active Directory, and I'm running into a pesky error. I've successfully synced another domain before, making the necessary proxy address adjustments, but now in the production environment, I get the error: ATTRIBUEVALUEMUSTBEUNIQUE. The error specifically points to a conflict with ProxyAddresses, even though I'm not creating any duplicates in the cloud. I've done a soft match to keep existing Microsoft 365 data intact, but I'm stumped on what's causing this issue. Has anyone else experienced this error? Any advice on what might be triggering the ProxyAddresses conflict? Thanks for your help!
4 Answers
Don't forget about the MailNickName attribute! If it’s not set for each user in your local AD, that could be the issue. It should just be the beginning part of their email; for instance, if the email is smarsh@contoso, make sure MailNickName is simply 'smarsh'. This might help resolve the proxy address conflict you're seeing.
You might want to consider switching from AD Connect to Cloud Connect Sync. They have some differences in features, so make sure those limitations are alright for you, but managing without the SQL Database or the Metaverse makes things a lot easier!
Have you looked into what the "ObjectIdInConflict" maps to? Sometimes the attribute causing the issue might not match the one on the conflicting object. Properties like UPN, mail, and proxyAddresses all come into play during conflict checks.
Have you checked if any admin accounts have the same proxy email address as your regular users? It can sometimes cause conflicts like this when you're syncing. I ran into that before and it was the source of the issue for me.
I double-checked and there aren't any admin accounts with conflicting proxy addresses. Everything seems clear on that front.