Solution Resolution for Lync 2013 Delete the sign in informationĭuring the sign in process, Lync 2013 caches your credentials and other information about its connection to Skype for Business Online.

Part of the certificate chain is untrusted and the certificate chain fails validation.The Skype for Business Online personal certificate or the cached credentials are corrupted or are out of date.The certificates cannot be acquired or validated. The Microsoft Online Services Sign-In Assistant is out of date.This issue may occur if one or more of the following conditions are true: There was a problem verifying the certificate from the server. If the problem continues, please contact your support team.Īdditionally, 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. When a Microsoft 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.

Skype sign in not working