Meeting invitations are not sent from Outlook in Skype for Business

Symptoms

Consider the following scenario:

• You're on a computer that has Microsoft Outlook 2010 or Outlook 2013 and Microsoft Skype for Business installed.
• The Skype for Business client has the March 8, 2016 update applied.
• You have the Use Auto-Complete list to suggest names when typing in the To, Cc and Bcc lines option enabled in Outlook.
• You create an online meeting, and then you select the meeting recipients from cache instead of the global address list (GAL).
• You select the send option to send a meeting invitation.

In this scenario, you receive the following error message:

The request failed. Please try again. Make sure that you are signed in to Skype for Business.

Cause

This problem occurs because of a known issue in the KB 3114831 version of UCAddin.dll (a Skype for Business plug-in for Outlook).

Resolution

To fix this problem, install the June 7, 2016 update (KB3115033) for Microsoft Lync 2013 (Skype for Business).

Workaround

To work around this problem, clear the Auto-Complete cache. To do this, use one of the following methods.

Method 1

Change the manner in which the Skype for Business Add-in for Outlook (UCAddin.dll) resolves recipients for meetings. To do this, create the following registry key:

Subkey location: HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Lync\AddinPreference

DWord name: RecipientResolutionMode

Value data (decimal): 2

Method 2

Follow these steps:

1. Open Outlook Options.
2. On the Mail tab, locate the Send messages section.
3. Clear the Use Auto-Complete List to suggest names when typing in the To, CC, and Bcc lines check box. The, click the Empty Auto-Complete List button.

More information

Still need help? Go to Microsoft Community.