- The software is out of date.
- The Lync client is out of date.
- The Microsoft Online Services Sign-In Assistant is out of date.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- The Skype for Business Online personal certificate or the cached credentials are corrupted or are out of date.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.
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.
Did this fix the problem?
- Check whether the problem is fixed.
- We'd appreciate your feedback. To provide feedback or to report any issues with this solution, please leave a comment on the "Fix it for me" blog or send us an email message.