Intermittent Outlook Anywhere Connectivity issue in SBS 2008.

The Official SBS Blog: Slow Connectivity for Outlook Anywhere and Sites that use the SBS Web Applications App Pool. https://blogs.technet.com/sbs/archive/2009/02/10/slow-connectivity-for-outlook-anywhere-and-sites-that-use-the-sbs-web-applications-app-pool.aspx

The post below is a workaround, for the official solution to this issue, please refer to the link above.

[This post comes to us courtesy Rituraj Choudhary]

You may experience the following issue in SBS 2008:Outlook Anywhere is very inconsistent and hardly connects. If you look at Outlook connection Status, it waits at Type Directory or Mail.

In the HTTPERR (under C:\Windows\System32\LogFiles) logs, you may find something like:

2008-11-13 16:55:10 124.124.68.131 40652 10.0.1.201 443 HTTP/1.1 RPC_IN_DATA /rpc/rpcproxy.dll?SBSDC1.CONTOSO.local:6004 400 0 BadRequest SBS+Web+Applications+application+pool
2008-11-13 16:56:01 124.124.68.131 40652 10.0.1.201 443 HTTP/1.1 RPC_IN_DATA /rpc/rpcproxy.dll?SBSDC1.CONTOSO.local:6004 400 0 Connection_Dropped SBS+Web+Applications+application+pool
These errors may appear for port 6001, 6002 and 6004.

If you enable Failed Request Tracing Rules on the /Rpc Virtual Directory, in the %SystemDrive%\inetpub\logs\FailedReqLogFiles\W3SVC3 xml files you may find something like:

Url: https://remote.contoso.com:443/rpc/rpcproxy.dll?SBSDC1.CONTOSO.local:6004
App Pool: SBS Web Applications application pool
Authentication: NOT_AVAILABLE
User from token:
Activity ID: {00000000-0000-0000-7827-0080000000D6}
Site: 3
Process: 7476
Failure Reason: STATUS_CODE
Trigger Status: 400
Final Status: 400
Time Taken: 70593 msec
Warning: SET_RESPONSE_ERROR_DESCRIPTION
ErrorDescription: ASP.NET detected invalid characters in the URL.
Warning: MODULE_SET_RESPONSE_ERROR_STATUS
ModuleName: HttptoHttpsRedir
Notification: 1
HttpStatus: 400
HttpReason: Bad Request
HttpSubStatus: 0
ErrorCode: 2147952454
ConfigExceptionInfo
Notification: BEGIN_REQUEST
ErrorCode: An existing connection was forcibly closed by the remote host. (0x80072746).

Resolution:
The IIS thinks the above mentioned URL to be malformed (Bad Request) and does not process the request further. This usually happens because of the corrupt configuration settings in the web.config file.

Renaming/deleting the web.config referred in the SBS Web Application application pool should resolve the issue.

Alternately, if a web.config is referred to by the /Rpc virtual directory, modify the <modules> .. .. ..<\modules> section in C:\Windows\system32\RpcProxy\web.config from:

<modules>
<remove name="HttptoHttpsRedir" />
<add name="HttptoHttpsRedir" type="Microsoft.WindowsServerSolutions.IWorker.IIS.Modules.HttpToHttpsRedir,HttpToHttpsRedir,Version=6.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" preCondition="" />
</modules>

to:

<modules>
<remove name="HttptoHttpsRedir" />
</modules>