softphone microphone dysfunction, but only within our office

Softphone doesn't transmit voice on calls to extensions within our office for the past two weeks, normal audio reception from those extensions with softphone. My laptop is on the same LAN at my office as the polycom vvx500 IP phones. Bidirectional audio functions normally with softphone to outside numbers, including my cellphone. the built-in microphone array on my laptop functions normally for other windows applications, and the troubleshooting section on softphone indicates normal microphone function. Rebooting the phone modem and the little phone server had no impact.  No one but me had been using softphone, but I had one of my employess install it on her laptop, with the same microphone issue. Tech support has created a ticket for us. is anyone else having this problem?