In the window that opens, select the Outlook profile, and then select the OK button.

Select the Session tab, and then select the Logon option.

Open the MFCMAPI tool, and then select OK.

If you have the 64-bit version of Outlook installed, you must install the 64-bit build of the MFCMAPI tool. Use the MFCMAPI tool to delete the stuck messages. These problems are caused by a read receipt that is stuck in progress and that Outlook keeps trying to resend. Outlook displays a number next to the Outbox folder (for example: Outbox ) even though there are no messages in the Outbox.

You are continually prompted to log in to internet email. The server responded: 550 5.1.0 sender rejected. If you continue to receive this message, contact your server administrator or Internet service provider (ISP). Task - Sending' reported error (0x8004210b) : 'The operation timed out waiting for a response from the sending (SMTP) server. You may also receive an error message that resembles the following: For example, you see the following message in the Progress bar: Additionally, Outlook stops responding when you try to close it. Outlook continuously displays a message such as 'Sending message 4 of 6' in the Progress bar even though there are no email messages queued. You experience one or more of the following problems when you use Outlook:

2010 outlook read receipt