You have a MAPI application that uses Microsoft Office Outlook 2007 MAPI or Microsoft Outlook 2010 MAPI in online mode.
The MAPI application tries to access the Exchange server.
The MAPI application is multithreaded and reads a stream of data from a Microsoft Exchange Server 2010 server.
In this scenario, the MAPI application encounters MAPI_E_CALL_FAILED errors. Additionally, the following error is logged in the remote procedure call (RPC) Client Access log on the Exchange Server 2010 Client Access server:
Exception of type 'Microsoft.Exchange.RpcClientAccess.BufferTooSmallException' was thrown.
Note By default, the RPC Client Access log is located in the following folder:
This issue occurs because the Exchange server returns an ecBufferTooSmall response that the MAPI application cannot handle to a sequence of remote operations. The ecBufferTooSmall response is generated because the Exchange server detects that the sequence of remote operations may cause a potential loop between the server and the MAPI application. Therefore, the read stream operation fails with the MAPI_E_CALL_FAILED error.
To resolve this issue, install the following update rollup:
2685289 Description of Update Rollup 3 for Exchange Server 2010 Service Pack 2
After you apply this update rollup, the Exchange Server 2010 server returns the ecBufferTooSmall response only if the following conditions are true:
The RopReadStream remote operation is the first value in the remote operation package.
The remote operations package is in the maximum size.
There are no other remote operations in the remote operation package.
Otherwise, Exchange Server 2010 server will return the RopBufferTooSmall response, which the Outlook MAPI application can handle.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about random MAPI_E_CALL_FAILED errors in Exchange Server 2010, go to the following MSDN website: