The diagnostic will guide Outlook Not Sending or Receiving Email 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 The most common cause of an out-of-date account is an incorrect password.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

If there's a feature you think is missing from the Mail and FixTechGuide Windows update Outlook fix Calendar apps, or if a feature in isn't working properly, you can provide feedback directly to the Mail and Calendar team. Two-factor authentication helps protect your account by making it more difficult for someone else to sign in. It verifies your identity using your password and a contact method (also known as security info). If you would like to ask me another question in the future or follow up on your current question, you can add me as a favorite Expert.

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

It is possible for a corrupted Outlook profile to impede synchronization. Test other programs or websites to be sure Outlook is the only problem. If the connection is poor, consider restarting your modem/router or moving to a more reliable network. 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 is not from a trusted certifying authority." Check with your email provider for instructions about how to create an app password for your email account.

Check Antivirus and Firewall Settings

• If you're using an Exchange account that requires advanced settings, you'll need to remove the account and add it again using advanced settings.
• After you’re satisfied, turn off your firewall or antivirus program for a while.
• In the notification bar at the top of the app, select Fix account.
• Windows Defender Security Center is free security software that's included with Windows 10.
• 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.
• Tempted to create a Test Shared Mailbox, but thinking that wouldn't be an accurate test for inbound mail, etc. or just actually tested by the Users at all.
• We have shared five manual methods in this blog to resolve the Outlook syncing errors.
• However, I cannot find any reason why his account would do this only on our domain nothing is blocking our connection to Office 365.

However, in some situations these processes can take up to 24 hours. We're in the process of migrating from On-Premise Exchange to O365. I solve Office 365 mailbox sync delays have a couple of Users and a Shared Mailbox that were migrated and both Users are experiencing issues with the Shared Mailbox updating on a regular basis.

Free Methods to Remove Duplicate Items in Outlook 2016

If you're using an Exchange account that requires advanced settings, you'll need to remove the account and add it again using advanced settings. To add the account using advanced settings, see Add an account using advanced setup. Knowing the reasons behind the Outlook sync issues will help us to fix this problem and prevent issues in communication and workflow. 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 I check the sync log I see a lot of sync errors for Inbox, sent items and a few other folders.