Error message when you try to sign in to Lync Online: "Cannot sign in to Lync because this sign-in address was not found"

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Article ID: 2705378 - View products that this article applies to.

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When you try to sign in to Microsoft Lync Online, you receive the following error message:
Cannot sign in to Lync because this sign-in address was not found. Please verify the sign-in address and try again. If the problem continues, please contact your support team.


To resolve this issue, first make sure that the user is licensed for Lync Online in the Microsoft Office 365 portal. After the user is licensed, he or she will be displayed in the Lync Online Control Panel or Lync Admin Center in the list of users.

If the user is licensed for Lync Online and still can't sign-in, set the value of msRTCSIP-UserEnabled to TRUE in the on-premises Active Directory schema, force a directory synchronization, and then wait 30 minutes. To do this, follow these steps:
  1. Open Active Directory Service Interfaces Edit (ADSIEdit) from the on-premises domain controller. For information about ADSIEdit, go to the following Microsoft website. (This includes information about how to add ADSIEdit to the Microsoft Management Console [MMC].)
    TechNet: Adding ADSI Edit to MMC
  2. Locate the user who can't sign in to Lync Online. To do this, build an LDAP query in ADSIEdit. For help in building the appropriate query and in locating the correct user, go to the following Microsoft website:
    TechNet: Using ADSI Edit
  3. When the correct user is found, change the msRTCSIP-UserEnabled attribute to TRUE.
  4. Use the Force the Directory Sync Tool to sync with Microsoft Office 365, and then wait approximately 30 minutes for the change to take effect in Office 365. 

    For more information about how to synchronize your directories, go to the following Microsoft website:
    Synchronize your directories


This issue may occur if one or more of the following conditions are true:
  • You are running the Active Directory Sync Tool together with an on-premises Active Directory schema.
  • You have or previously had a deployment of Microsoft Lync Server 2010 or of Microsoft Office Communications Server 2007, together with Active Directory schema extensions.
  • In a previous deployment, the msRTCSIP-UserEnabled attribute was set to FALSE. This attribute value is synced to Office 365 and disables the Lync Online license of the Lync Online user who can't sign in. (However, the Lync Online license is still displayed as enabled in the Office 365 portal.)

Still need help? Go to the Office 365 Community website.


Article ID: 2705378 - Last Review: October 10, 2013 - Revision: 11.0
Applies to
  • Microsoft Office 365 for enterprises (pre-upgrade)
  • Microsoft Office 365 for education  (pre-upgrade)
  • Microsoft Lync Online
o365 o365a o365e o365022013 after upgrade o365062011 pre-upgrade o365m KB2705378

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