When installing Lync2013 on your iPhone or iPad you may see an error that says "Can't verify the certificate from the server. Please contact your support team." and you can't sign into Lync on the device.
In this case, please submit a helpdesk ticket. We will need the device in person to install the certificate manually as well as the password pin to unlock it. It should take roughly 10 - 15 minutes to do. In case you want to know more information, you can click the links below.