If you can sync your email when the firewall is turned off, you'll need to allow the 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. Test other FixTechGuide email error solutions programs or websites to be sure Outlook is the only problem.

Method 4: Recreating the Outlook Profile

However once I joined this computer back to the domain and let it sit for a few days it was also working fine. Once the client started using Outlook again after some time has passed the issue had come back. I’ve tried to set cache mode from 1 year all the way down to a few days. If your password isn't the problem, you might have a certificate error. If so, you'll see a message that says, "There is a problem with the server's security certificate. The security certificate rebuild Outlook data file quickly is not from a trusted certifying authority."

Check the connectivity to your email server

• I’ve unchecked download shared folders when setting up a new Outlook profile.
• I’ve been in contact with Microsoft they had me migrate his account\data to another server this did not fix it.
• Before you begin, make sure that your device has the latest operating system and app updates.
• Below are the steps I’ve taken to try to resolve this issue.
• Firewalls and antivirus software might prevent you from syncing your email and calendar events.
• This solution will be beneficial for users who are facing Outlook syncing issues because of corrupted PST or OST files.

You'll also receive a mail (to the alternate email and to your admin email) from Microsoft FixTechGuide email error Solutions 365 that indicates your tenant has encountered directory synchronization errors. For details see Identify directory synchronization errors in Microsoft 365. I still have it turned on on my laptop and it has not shown any issues yet.

Methods to fix Microsoft Outlook syncing error

I ran the PSTscan tool to check for anomalies on the OST file (which it found and repaired but the issue still occurs). However, with one particular client no matter what changes are made these sync issue still occur. We're sorry you're having problems with the Mail and Calendar apps for Windows 10. To fix the issue, please try each of the following solutions in order.

Microsoft Outlook Sync issues

Always make sure your profile and settings are set up correctly, your software is up to date, and your connection is steady. The causes of sync issues and local failures in Outlook are explained in this guide, along with practical troubleshooting and resolution techniques. You can extract and recover all of your mail items to a PST file using sophisticated OST File to PST Converter software if your OST file becomes unavailable or orphaned. Third-party firewalls or antivirus software might prevent you from syncing your email and calendar events. Check the software documentation to learn how to temporarily turn it off.