There was a problem acquiring a personal certificate required to sign in. If the problem continues, please contact your support team.
If you are still experiencing issues after trying out Microsoft’s help with removing certificates and Credentials from the Credentials Manager found here http://support.microsoft.com/kb/2604176 it might be because you have setup Federated Single Sign on and have a self-signed or untrusted certificated publishing your ADFS
The best way to resolve this issue is to trust the certificate of your ADFS published site or alternatively stop being so cheap and purchase a certificate online 🙂 However I am cheap and therefore used the following steps to trust my self-signed certificate.
Go to the HTTPS address of the ADFS published site (https://adfs.domain.com) and click certificate error in the URL Navigation bar.
Then click View Certificates
Once the Certificate tab opens click Install Certificate
Select Place all certificates in the following store and Browse to ‘Personal’ and select OK
Now you will need to do the procedure again but this time adding the certificate to ‘Trusted Root Certification Authorities’
Once completed you should be able to now sign-in on Lync 2010 Online for Office 365!