The other solution to fix Outlook sync issues is recreating Microsoft Outlook profile. Follow each step carefully to resolve synchronization errors. Sometimes an error appears in the Mail and Calendar apps when Microsoft Outlook Email Repair Tool Online the apps try to sync new email or calendar events. We’ve had sync issues with employees from time to time however, re doing the mail profile or wiping the Windows profile usually fixes it.

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 clear Outlook credentials manager is not from a trusted certifying authority."

Check the connectivity to your email server

• We have shared five manual methods in this blog to resolve the Outlook syncing errors.
• The client has a computer off the domain at home that his work email is tied to and he has never had any of these issues in Cache mode with that device.
• An app password is used instead of your normal account password for apps that don't support two-factor authentication.
• Once the client started using Outlook again after some time has passed the issue had come back.
• If it does, you might need to include Outlook exceptions in the settings of your security program.
• When they go back to the message and press send they get an error that the message has been deleted.
• The other solution to fix Outlook sync issues is recreating Microsoft Outlook profile.

You'll also receive a mail (to the alternate email and to your admin email) from Microsoft how to fix Outlook not opening today 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

If users are facing syncing issues in Outlook due to corrupt Outlook data files, they must choose a professional tool, like Shoviv OST to PST Converter Tool. This software allows users to process numerous OST files at once without any size limitations. Moreover, it maintains the folder hierarchy and metaproperties of the data when processing Outlook data files.