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Article ID: 111653, created on Jul 18, 2011, last review on May 10, 2014

  • Applies to:
  • Operations Automation 5.x


A new Outlook profile cannot be configured for Exchange mailbox with the following error:
The action cannot be completed. The connection to Microsoft Exchange is unavailable. Outlook must be online or connected to complete this action.
Sometimes, Outlook may stall during a particular operation and report the following error message: The Microsoft Exchange Server computer is not available.
These symptoms appear only if Exchange 2010 SP1 is deployed on Exchange CAS (Client Access Server) servers.


Outlook may reach its limits related to the RPC protocol defined in the default throttling policy. This default throttling policy is assigned to all Exchange 2010 mailboxes created by Parallels Operations Automation (POA).


We recommend that you update the default Exchange throttling policy and set the following values for parameters related to the RPC protocol, run the cmdlet below in the Exchange Management Shell e.g. on Exchage CAS server:

Get-ThrottlingPolicy | where {$_.IsDefault -eq $true} | Set-ThrottlingPolicy -RCAMaxConcurrency 100 -RCAPercentTimeInAD $null -RCAPercentTimeInCAS $null -RCAPercentTimeInMailboxRPC $null -CPAMaxConcurrency 100 -CPAPercentTimeInCAS $null -CPAPercentTimeInMailboxRPC $null

Important: run the command above as single line.

caea8340e2d186a540518d08602aa065 2554725ed606193dd9bbce21365bed4e 5356b422f65bdad1c3e9edca5d74a1ae e12cea1d47a3125d335d68e6d4e15e07

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