When Outlook tries to retrieve Autodiscover information for an Exchange Online mailbox in an Exchange hybrid environment, you may experience a delay or unexpected results.
The client is locating one or more service connection point (SCP) objects for the Autodiscover service in the local Active Directory forest.
To resolve this issue, use one of the following methods.
Method 1: Disable SCP lookup
Important Follow the steps in this section carefully. Serious problems might occur if you modify the registry incorrectly. Before you modify it, back up the registry for restoration in case problems occur.
Open Registry Editor.
Locate and then select the following registry subkey:
Note The x.0 placeholder corresponds to the version of Outlook (16.0 = Outlook 2016, 15.0 = Outlook 2013).
On the Edit menu, point to New, and then click DWORD Value.
Type ExcludeScpLookup, and then press Enter.
Right-click the ExcludeScpLookup value that you created, click Modify, type 1 in the Value data box, and then click OK.
To control Outlook Autodiscover by using Group Policy, see the following Microsoft Knowledge Base article:
2612922 How to control Outlook AutoDiscover by using Group Policy
Method 2: Remove the Exchange SCP objects
Warning This procedure requires Active Directory Service Interfaces Editor (ADSI Edit). Using ADSI Edit incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems that result from the incorrect use of ADSI Edit can be resolved. Use ADSI Edit at your own risk.
Open ADSI Edit.
Right-click ADSI Edit, click Connect to, click Configuration in the Select a well known Naming Context box, and then click OK.
Exchange Server 2016 Enterprise Edition, Exchange Server 2016 Standard Edition, Microsoft Exchange Server 2013 Enterprise, Microsoft Exchange Server 2013 Standard, Microsoft Exchange Server 2010 Enterprise, Microsoft Exchange Server 2010 Standard, Microsoft Exchange Online