Slow Connectivity for Outlook Anywhere and Sites that use the SBS Web Applications App Pool

Article ID: 2000859 - View products that this article applies to.
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You are unable to connect to Outlook Anywhere or connections are very slow.  All sites that use the SBS Web Applications app pool are either inaccessible or very slow to load.


The reason this happens is due to the default setting of 2.0’s default maximum concurrent requests of 12 per CPU. When using RPCProxy which is used by both Outlook Anywhere and TS Gateway, the connections are asynchronous which can cause you to hit the limit of 12 pretty fast. For more detail on thread usage and this limit please read.


  1. Open regedit with administrative permissions.
  2. Create the below DWORD and set its value to 5000 decimal to increase the limit of concurrent requests.

    Location: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ASP.NET\2.0.50727.0\

          Name: MaxConcurrentRequestsPerCPU

More Information

Additional information on this issue can be found in the following blog post:



Note This is a "FAST PUBLISH" article created directly from within the Microsoft support organization. The information contained herein is provided as-is in response to emerging issues. As a result of the speed in making it available, the materials may include typographical errors and may be revised at any time without notice. See Terms of Use for other considerations.


Article ID: 2000859 - Last Review: January 15, 2015 - Revision: 5.0
Applies to
kbnosurvey kbarchive KB2000859

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