I had to rename a user account in active directory (sync in place). The primary email address won't change/update.

Hi @Holly Baker

Thank you for bringing this to our attention. I understand how frustrating it can be when expected changes, such as a primary email address update, don’t reflect properly after renaming a user in Active Directory. 

As a forum moderator, I’m here to provide guidance and direct you to reliable resources. While I don’t have access to your environment or the ability to perform technical actions, I can help clarify the issue and outline standard steps that may help resolve it. 

Based on the error message you shared, the issue appears to be related to directory synchronization between your on-premises Active Directory and Exchange Online. In many cases, the primary email address does not update as expected because of how the proxyAddresses attribute is managed in Active Directory. 

To address this, your IT administrator may need to: 

• Ensure the proxyAddresses attribute includes the new primary SMTP address using uppercase SMTP:. 
• Update the mail and userPrincipalName attributes to match the new name. 
• Perform a delta sync using Azure AD Connect. 
• Verify that the primary email has updated correctly in Exchange Online via PowerShell. 

For a detailed explanation of how the proxyAddresses attribute is interpreted and synchronized, please refer to Microsoft’s official documentation: How the proxyAddresses attribute is populated in Microsoft Entra ID | Microsoft Learn 

If you have verified all these points and the issue persists, it may indicate a more complex state issue with the object in Exchange Online. In that case, the recommended next step is to open a support ticket with Microsoft so a technical engineer can perform a deeper analysis of the synchronization logs and the object’s properties. 

Please keep us updated on your progress, as your findings could help others in the community. 

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