You can’t sign in to Skype for Business Online because the certificate can’t be acquired or validated

Applies to: Skype for Business OnlineMicrosoft Windows XP ProfessionalMicrosoft Windows XP Home Edition


When an Office 365 user tries to sign in to Skype for Business Online (formerly Lync Online) by using Lync 2010 or Lync 2013, the user receives the following error message:
There was a problem acquiring a personal certificate required to sign in. If the problem continues, please contact your support team.
Additionally, when you try to sign in to Lync after a network outage or a Skype for Business Online service outage, you receive the following error message: 
Cannot sign into Lync. There was a problem verifying the certificate from the server.


This issue may occur if one or more of the following conditions are true:
  • The software is out of date.
    • The Lync client is out of date.
    • The Microsoft Online Services Sign-In Assistant is out of date.
  • The certificates cannot be acquired or validated.
    • The Skype for Business Online personal certificate or the cached credentials are corrupted or are out of date.
    • Part of the certificate chain is untrusted and the certificate chain fails validation.



If the issue persists after you perform these troubleshooting steps, contact Microsoft Office 365 technical support or the Microsoft Office 365 Community forums. In certain cases, the Active Directory Domain Services user account may be incomplete or corrupted. Therefore, Skype for Business Online can't generate a personal certificate. This may not affect all of a tenant's accounts because the effect depends on the state of the server when the user account was created.

To narrow the issue, determine whether the issue occurs for multiple user accounts on the same computer. Then, try to sign in to Skype for Business Online from the same computer by using multiple user accounts. This process indicates whether the problem is related to the configuration of the computer or an issue with the Skype for Business Online user account.

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