Both of our authentication methods can fail if the Enterprise Applications entry for the sync in Azure AD is deleted or if it has had its permissions modified. We go above and beyond the average software reseller because we built our business on trust. As active members in the IT community, we work to support our clients’ businesses and provide them with peace of mind. After these instructions, ensure the sync settings are correct and check everything is working well. For managed setups, we can push a PowerShell script with Intune or Group Policy to clear cached tokens on all devices. A quick look at the Microsoft Entra Connect Health portal helps us see if sync tasks are current and the connection to Microsoft 365 is steady.

• The sync will fail if it can't find any users that comply with your filtering preferences or the system's requirements for user records.
• After performing these steps, Outlook’s all folders will be synced to the server.
• If password writeback isn’t enabled or the service account doesn’t have the right permissions, new passwords won’t update in Active Directory.
• This blog talks about the causes behind Outlook synchronization errors and a few solutions to fix Outlook sync issues.
• Check that your password change actually synced between your on-premises Active Directory and Microsoft Entra ID (formerly Azure AD).
• That tells us if the new credentials made it to the cloud directory.
• If the old password still works, the reset probably hasn’t synced.

Troubleshooting Microsoft 365 sync issues

This pops up a lot after admins reset a password in the Microsoft 365 admin center. That changes the password in Microsoft Entra ID, but not right away in your local Active Directory. You end up with mismatched passwords between the cloud and your local network. If you don't wish an inactive user to be made active by the M365 sync, you can add the user's email address to the sync forbid list. You can do this in the Microsoft 365 Sync Wizard on the configuration page of your platform settings. Knowing the reasons behind the Outlook sync issues will help us to fix this problem and prevent issues in communication and workflow.

Common Reasons Behind Outlook Sync Issues

I would greatly appreciate mailbox not updating on IMAP it if you could let me know if your issue has been resolved. TrustedTech delivers unbeatable customer service, with experts in licensing and high-level technicians always on-call to answer your tech issues in-depth. TrustedTech is a Microsoft CSP Direct Bill Partner with all six Solutions Partner designations and decades of expertise in licensing, support, and cloud infrastructure.

Address

Now, we will verify the server settings to fix the Outlook synchronization error. Once you have completed the steps to fix Outlook sync errors, kindly check if the error has been fixed or not. The M365 sync establishes a synced dataset based on your M365 data and the filtering configuration of your sync.

Get Expert Help from TrustedTech

The Summary sheet on the spreadsheet attachment of your sync summary includes an Updated User Count and User Limit. These figures will give you an impression of how far over the limit the account is. Sync failure alerts do not always include a full summary or attachment, you can run a test sync to obtain this data. With directory synchronization, you can continue to manage users and groups on-premises and synchronize additions, deletions, and changes to the cloud. But setup is a little complicated and it can sometimes be difficult to identify the source of problems. We have resources to help you identify potential issues and fix them.

What should I do if my sync failed due to authentication issues?

We also scan Event Viewer logs under Applications and Services rebuild Outlook data file quickly Logs → Directory Synchronization for Event IDs like 650–657 (for sync activity). Errors like Event ID 611 point to invalid replication data or outdated software. The error message in the Summary sheet of the Sync Summary spreadsheet attachment can also highlight the reason for this.



On the sync server, we open the Synchronization Service Manager and check that the last sync finished without errors. Azure AD Connect handles password sync, but it runs on a schedule—usually every 30 minutes. So, if you just changed your password, there might be a short window where your old password still works and the new one hasn’t reached every system.

Discover how IT leaders can address key Microsoft Copilot questions on cost, deployment, security, and integration to maximize ROI and adoption. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.



Devices sometimes keep using cached passwords even after a successful sync. If users access multiple apps with the same login, we make sure Single Sign-On (SSO) settings line up so the new password works everywhere in Microsoft 365. We look at audit logs in the Microsoft 365 admin center to see when and where the password changed. That tells us if the new credentials made it to the cloud directory. We tell users to sign out completely and remove stored credentials from Windows Credential Manager or their device’s keychain.

We check that the Work or School Account in Windows Settings is active and linked to the right domain. The sync will fail if the groups you selected to load users from no longer exist in Azure AD. Typically this is because the selected groups have been deleted from Azure clear Outlook credentials manager AD since the M365 sync was configured on your account.