When a Lync phone (in my scenario a Polycom CX700 and a Polycom CX3000) is connected to a Computer using a USB cable you can use the Lync client on the PC to logon to the Lync servers. An additional pop-up is shown where the credentials have to be entered:
But the Lync client will not logon and the pop-up appears all the time. At the same time you may see a message like “Cannot download certificate because domain is no accessible. If the problem persists, contact your system administrator” or something like this.
Continue reading Lync client and (Polycom phone) will not sign in