Consider the following scenario:

  • You are in a Microsoft Exchange Server 2013 environment that has Cumulative Update 3 to Cumulative Update 6 installed.

  • You have two or more Active Directory sites (Site 1 and Site 2), and both sites have Client Access server installed.

  • You have a mailbox in Site 1.

  • You try to log on to Exchange Admin Console (EAC) from the Client Access server in Site 2.

In this scenario, you are logged in to Outlook Web App instead of EAC. If you do not have a mailbox in Site 1, you'll receive the following error message when you try to log on to EAC from the Client Access server in Site 2:

Something went wrong.

A problem occurred while you were trying to use your mailbox. 

X-OWA-Error: Microsoft.Exchange.Data.Storage.UserHasNoMailboxException

X-OWA-Version: OWA-Version

X-FEServer: FEServer

X-BEServer: BEServer

Date: Date and Time


This issue occurs because the HTTPProxy component does not handle the request correctly.


To resolve this issue, install Cumulative Update 7 for Exchange Server 2013.


To work around this issue, use the URL of the Client Access server in the site that has the user mailbox to log on to EAC. For users who do not have the mailbox, use the URL of the Client Access server that hosts arbitration mailbox SystemMailbox{bb558c35-97f1-4cb9-8ff7-d53741dc928c}.


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

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