In Outlook, sometimes your outgoing messages get stuck in your outbox and just won't send. Learn about some ways to get them moving.

Learn how to fix Outlook.com email sync issues if you can't receive or send messages.

Check to see if the new Outlook toggle is turned on or off. If it's on, please go to Troubleshooting Outlook issues. As a first step, go to the Classic Outlook troubleshooters page and select one of the troubleshooters listed. If that doesn't work, contact support for assistance.

There are multiple ways for you to send and receive email, and multiple versions of Outlook available. If the images in these topics don't match what you see on your screen, you might be using a different version of Outlook.

If you receive one or more of these error messages, you may experience performance issues until Outlook finishes the reconciliation process for the .ost file or for the .pst file.

If you are having problems with new or classic Outlook for Windows not responding, hangs, freezes, or stops working, there are a few things we can help with to get you back to using Outlook.

Last updated: June 2026. For issues that are not covered on this page, we have multiple tools to help you automatically diagnose and fix a range of Outlook problems. Need more help? Talk to support.

Having trouble connecting to your email from Outlook on your desktop? Follow these steps to let Outlook diagnose and fix errors in your Outlook mail profile that might be causing the issue.

When this problem occurs, the message remains in your Outbox folder until you manually initiate a Send/Receive operation (for example, press F9 or select send or receive).

When you try to accept a shared Outlook.com calendar using your Microsoft 365 for business account in Outlook 2016, you might receive the "Something went wrong" error or your sign-in might fail.