cer file to import it into your keychain. cer file, exit Lync on your Mac, double click the. Right click > All Tasks > Export > Next > No, do not export the private key > Select Base-64 encoded X.509 (.CER) > Next > Give it a name (fully qualified domain name) > Next > Finish ) with the intended purpose 'Server Authentication' Click on the certificate with the fully qualified domain name (i.e. Expand Certificates > Personal > Certificates
Open MMC > Add/Remove Snap-in > Select Certificates > Click Add > Select Computer account > Click Next > Local computer > Finish > OK
To resolve the 'Sign in to Microsoft Lync failed because the service is not available or you may not be connected to the Internet.' you need to reimport your Lync server certificate.Īsk your system administrator of the Lync server to export the server certificate and provide to you: This Fixed My issue, I make sure you always allow the trust in the last step. I used this solution below and my MBP back to login in my Lync server:
