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When you try to download an e-mail message from a POP3 server in Microsoft Office Outlook 2007 or in Microsoft Office Outlook 2010, it takes much longer than expected. For example, when you download a 1-megabyte (MB) message, the download process may take as long as one hour.
Additionally, when you send e-mail messages by using the SMTP server of an Internet service provider (ISP), the connection may time out. When this problem occurs, you may receive the following error message:
This problem occurs if a network hardware device, such as a router, does not support TCP Window Scaling. TCP Window Scaling is a new Windows Vista feature.
Task 'Main - Sending and Receiving' reported error (0x800CCC0F) : 'The connection to the server was interrupted. If this problem continues, contact your server administrator or Internet service provider (ISP).'
This article helps you fix the problem. To have us fix this problem for you, go to the “Fix it for me” section. If you would rather fix this problem yourself, go to the “Let me fix it myself” section.
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To determine whether this problem is caused by a network hardware device that does not support TCP Window Scaling, follow these steps:
Check whether the problem is fixed. If the problem is fixed, you are finished with this article. If the problem is not fixed, you can contact support
To see the current configuration for the autoTuningLevel parameter, follow these steps:
The TCP/IP stack in Windows Vista tunes itself in most environments by using larger default window sizes than in earlier versions of Windows. Instead of using a hard-coded default receive window size, TCP automatically adjusts the window size to increase the percentage of full-sized TCP segments that are used during bulk data transmission. This helps limit the number of segments that are sent when large sets of data are transmitted.
When auto-tuning is enabled in Windows Vista, Receive the Window Auto-Tuning feature continually determines the optimal true receive window size by measuring the bandwidth delay product and the application retrieve rate. Then, Receive Window Auto-Tuning adjusts the maximum receive window size based on the changing network conditions.
For more information about the Next Generation TCP/IP stack that includes Receive Window Auto-Tuning, visit the following Microsoft Web site:
http://technet.microsoft.com/en-us/library/bb878127.aspxFor more information about Windows TCP implementation features, visit the following Microsoft Web site:
http://msdn2.microsoft.com/en-us/library/ms819768.aspxFor more information about TCP receive window size and about window scaling, visit the following Microsoft Web site:
http://msdn2.microsoft.com/en-us/library/ms819736.aspxFor more information about RFC 1323, visit the following Internet Engineering Task Force Web site:
http://go.microsoft.com/fwlink/?linkid=6746Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information.
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