Regardless of their mailbox size, Microsoft set a default OST size for a reason, while it can be changed, that doesn’t mean it should. 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.
How to resolve the issue of Outlook not syncing in Windows?
In the notification bar at the top of the app, select Fix account. If your password is incorrect, you'll see a message asking you to update your password. 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. If that doesn't solve your issue, try the solutions below.
Desktop (Old) Outlook Not Syncing Recent / All E-Mails - 'Kinda' Urgent
How to force Outlook to sync manually?
In some cases, there might be outages or network-related issues, such as problems with a VPN. Mail flow issues can also arise out of other circumstances, such as a user having a mailbox in both Exchange Online and Exchange on-premises. In some cases, an issue might be related to MDM settings, such as restrictions on Outlook functionality, or user account and mailbox settings in Exchange. Sometimes an error appears in the Mail and Calendar apps when the apps try to sync new email or Repair Office 365 installation errors calendar events. These syncing problems usually happen because of issues like a damaged Outlook profile, poor internet connection, or a corrupted OST file.
Want more options?
These syncing problems usually happen because of issues like a damaged Outlook profile, poor internet connection, or a corrupted OST file.For more information, see Add an account using advanced setup.If your password is incorrect, you'll see a message asking you to update your password.Online archive is only available online too, so no caching, hence it’s name.So, comments about his email box size aside (which I cannot change or make him clean up at this time), I need this fixed really fast today.For example, ActiveSync might not be enabled, or there might be a problem with the ActiveSync certificate settings.
When using Microsoft Teams on an iPhone, slow performance and app crashes can bring mobile work to a halt. Many issues come down to internet bandwidth or low storage space. If there's a feature you think is missing from the Mail and Calendar apps, or if a feature in isn't working properly, you can provide feedback directly to the Mail and Calendar team.
Emails not syncing until Outlook restart
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. 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. Why not limit the caching to a more reasonable 1 year, if they need to access things outside of this, they can, they just have to click ‘view messages on server’ to do so. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.
It’s best to cache what they need in an offline situation (for example, 1 year), then apply the archive to beyond this point. Online archive can take 24 hours or more to complete, it depends on what you have it set to archive. So, comments about his email box size aside (which I cannot change or make him clean up at this time), I need this fixed really fast today. 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). While we all use systems differently, I don’t think I have 100GB of data after working for my company almost 25 years, let alone this much email.