The diagnostic will guide connection status shows disconnected 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 The most common cause of an out-of-date account is an incorrect password.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 connection status shows disconnected 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 connection status shows disconnected 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

Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. These are the only two I've seen have this issue and I was wondering if you've seen this and figured out a 'fix'? 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.

Check Antivirus and Firewall 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.
• 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.

If you can sync your email when the firewall is turned off, you'll need to allow the reset cached Exchange mode 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

The Mail and Calendar apps for Windows 10 don't support two-factor authentication. If two-factor authentication is turned on for your account, you'll need to create an app password for that account. An app password is used instead of your normal account password for apps that don't support two-factor authentication. Before you begin, make sure that your device has the latest operating system and app updates. Try the general troubleshooting solutions in Troubleshooting Mail and Calendar apps for Windows 10. I regret that you are experiencing issues with your Microsoft Outlook slow synchronizing inbox message, and need help speeding up.