- SCP lookup
- HTTPS root domain query
- HTTPS Autodiscover domain query
- Local XML file
- HTTP redirect method
- SRV record query
- Cached URL in the Outlook profile (new for Outlook 2010 version 14.0.7140.5001 and later versions)
- Direct Connect to Office 365 (new for Outlook 2016 version 16.0.6741.2017 and later versions)
By default, Outlook will try one or more of these methods if it is unable to reach Autodiscover. For example, in a scenario with a machine not joined to a domain Outlook will try to connect to the predefined URLs (for example, https://autodiscover.contoso.com/autodiscover/autodiscover.xml) by using DNS. If that fails, Outlook will try the HTTP redirect method and, failing that, Outlook will try to use the SRV record lookup method. If all lookup methods fail, Outlook will be unable to obtain Outlook Anywhere configuration and URL settings.
Please see the Exchange Autodiscover Service White Paper appropriate for your version of Exchange for details on all of the different Autodiscover connection methods used by Outlook.
Exchange 2013 Autodiscover service:
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, go to the following article in the Microsoft Knowledge Base:
- Start Registry Editor.In Windows 10 and Windows 8, press the Windows Key + R to open a Run dialog box. Type regedit.exe and then press OK.In Windows 7, click Start , type regedit in the Search programs and files box, and then press Enter.
- Locate and then select the following registry subkey:
Notex.0 in this registry path corresponds to the Outlook version (16.0 = Outlook 2016, 15.0 = Outlook 2013, 14.0 = Outlook 2010, 12.0 = Outlook 2007).
- Review the following possible DWORD values that may be located under the \Autodiscover subkey.
- ExcludeLastKnownGoodURL (only applies to Outlook 2010 version 14.0.7140.5001 and later versions)
- ExcludeExplicitO365Endpoint (only applies to Outlook 2016 version 16.0.6741.2017 and later versions)
Note Some documentation states that the ExcludeSrvLookup value is used by Outlook in this scenario. Unfortunately, this documentation is incorrect as the ExcludeSrvLookup value does not exist in Outlook code. Only the ExcludeSrvRecord registry value is used by Outlook to control the SRV record lookup for Autodiscover. Therefore, if you find a value called ExcludeSrvLookup under the \Autodiscover subkey, you can safely change its value to 0.
- Repeat step 3 by using the following registry subkey:
Note x.0 in this registry path corresponds to the Outlook version (16.0 = Outlook 2016, 15.0 = Outlook 2013, 14.0 = Outlook 2010, 12.0 = Outlook 2007).
- Start Outlook.
- Press the CTRL key, right-click the Outlook icon in the notification area, and then click Test E-mail AutoConfiguration.
- Verify the e-mail address is correctly entered in the E-mail Address box.
- Enter your password if you are not logged into a domain or if you are accessing a mailbox that is different from your mailbox.
- Click to clear the Use Guessmart and the Secure Guessmart Authentication check boxes.
- Click Test.
- Review the details on the Log tab.
Compare this information when only the ExcludeScpLookup value is set to 1.
Note Ignore the failures in these figures because this information is intended only to show you the different lookup attempts that are made by Outlook.
Also, if you enable logging in Outlook (2007 or 2010), the different Autodiscover lookup attempts can be found in the %temp%\Olkdisc.log file. This log file also includes any registry settings you have configured to exclude any of the Autodiscover lookup methods. In the following figure, you can clearly see that the ExcludeScpLookup and ExcludeHttpsAutoDiscoverDomain values are both set to 1.
For more information about the client-side management and administration of Autodiscover, go to the following Knowledge Base article:
2612922 How to control Outlook AutoDiscover by using Group Policy