Microphone sometimes doesnt work

[p4blo]

Hi to all Experts,

I have a call center with 30 seats. Were using VERSION: 2.12-563a BUILD: 160801-2119 and Windowsk 7 Home Edition on Agents PCs. Were having a problem like this, all is working fine except each 20-30 calls the customer cant hear the agents and sometimes customer's cant hear my agents and having a poor quality of sounds. In order to resolven this roblem, agents have to make this steps:
1. logg off vicidial campaing
2. log in vicidial campaing
After that everything workin fine, customer hear them well and they her customer great. After next 20-30 calls the problem show up again. Our headset is working fine because we use it on calling skype. Internet connection is 10mbs Symmetrical.

Waiting for a help