Outlook 2013 cannot connect to Exchange Server 2013 or Exchange Server 2016 using MAPI over HTTP when a proxy is enabled

Symptoms
Consider the following scenario:
  • You are using Microsoft Outlook 2013 version 15.0.4569.1506 or a later version.
  • You are connecting to a Microsoft Exchange Server 2016 or Microsoft Exchange Server 2013 Service Pack 1 (SP1) mailbox by using the MAPI over HTTP transport protocol.
  • On your Outlook client computer, you have a proxy enabled that has your own domain listed as an exception.

In this scenario, Outlook cannot connect to Exchange Server, and the Status Bar in Outlook displays "DISCONNECTED."
Cause
Outlook cannot connect to the Exchange Server by using MAPI over HTTP when a proxy is enabled that has your own domain listed as an exception.
Resolution
To resolve this issue, install the February 10, 2015, update for Outlook 2013. For information about this update, click the following article number to view the article in the Microsoft Knowledge Base:
2956087 February 10, 2015, update for Outlook 2013 (KB2956087)

Workaround
If you cannot install the update that is mentioned in the "Resolution" section to resolve this issue, you can work around the issue by using one of the following options:

Option 1 

Remove your own domain name from the exceptions in the proxy settings. To do this follow these steps:

  1. In Internet Explorer, click Tools, and then click Internet Options.
  2. On the Connections tab, click LAN Settings.
  3. In the Proxy Server section, click Advanced.
  4. In the Exceptions section, remove your domain.
  5. Click OK three times.

Option 2 

Disable MAPI over HTTP. To do this, follow these steps:
  1. Exit Outlook if it is running.
  2. Start Registry Editor. To do this, use one of the following procedures, as appropriate for your version of Windows:
    • Windows 8: Press Windows Key + R to open the Run dialog box, type regedit.exe, and then click OK.
    • Windows 7 or Windows Vista: Click Start, type regedit.exe in the search box, and then press Enter.

  3. In Registry Editor, locate and then click the following registry subkey:

    HKEY_CURRENT_USER\Software\Microsoft\Exchange

  4. On the Edit menu, point to New, then select DWORD Value.
  5. Type MapiHttpDisabled as the name of the DWORD Value, and then press Enter.
  6. Right-click MapiHttpDisabled, and then click Modify.
  7. In the Value data box, type 1, and then click OK.

Note The MapiHttpDisabled registry value is intended for testing only.
More information
For more information about the requirements for MAPI over HTTP connections, go to the following Microsoft TechNet website:
Properties

Article ID: 2986802 - Last Review: 10/01/2015 07:27:00 - Revision: 4.0

Microsoft Outlook 2013 Service Pack 1, Exchange Server 2016 Enterprise Edition, Exchange Server 2016 Standard Edition, Microsoft Exchange Server 2013 Service Pack 1

  • KB2986802
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