The diagnostic will guide guide to Office 365 sign-in errors you to resolve various error conditions that can cause mailboxes to not be created. The most common cause of an out-of-date account is an incorrect password. In the notification bar at the top of the app, select Fix account.

Turn off Windows Defender Security Center

It also provides the option to export the Outlook OST file into Office 365 and Live Exchange mailboxes. This software also has a splitter option to split large-sized PST files into smaller ones, helping users prevent oversized PST file issues. Outlook sync issues can be because of corrupted Outlook OST or PST files. Therefore, now we will know the steps to repair the Outlook data file. We’ve Credential Loop In Microsoft 365 had sync issues with employees from time to time however, re doing the mail profile or wiping the Windows profile usually fixes it. In some cases setting up a new computer replacement was the only option to fix these odd Outlook Sync issues.

Check if two-factor authentication is turned on for your account

Once the client started using Outlook again after some time has passed the issue had come back. I ran the PSTscan tool to check for anomalies on the OST file (which it found and repaired but the issue still occurs). I’ve tried to set cache mode from 1 year all the way down to a few days.

Check Antivirus and Firewall Settings

• It is possible for a corrupted Outlook profile to impede synchronization.
• Incorrect Outlook settings can also be one of the reasons behind Outlook synchronization errors.
• I’m at wits end and Microsoft stopped helping me because they feel the problem is on our end.
• Here, we will discuss the five manual methods to fix sync issues in Outlook or OWA.
• To fix the issue, please try each of the following solutions in order.
• If you still can't sync your email after removing your account and adding it again, you might need to add the account using advanced setup.

If you can sync your email when the firewall is turned off, you'll need to allow the fix MFA prompts not working Mail and Calendar apps through the firewall. Windows Defender Security Center is free security software that's included with Windows 10. If you haven't installed alternative security software, you should temporarily turn off Windows Defender Security Center.

Free Methods to Remove Duplicate Items in Outlook 2016

Check the software documentation to learn how to temporarily turn it off. There are various methods to resolve the Outlook sync issues, including manual and third-party solutions. Firstly, we will discuss a few manual methods to resolve this Outlook error and share the stepwise procedure of each method to successfully fix synchronization issues. Now, let us start with the manual processes to fix Outlook syncing errors. Firewalls and antivirus software might prevent you from syncing your email and calendar events. These syncing problems usually happen because of issues like a damaged Outlook profile, poor internet connection, or a corrupted OST file.