After doing an update and reinstalling Zoiper Classic 2.20 i found that my headset (Logitech H390 - USB) doesn't work with Zoiper, the system does recognize the headset and I can hear anything outside of Zoiper. I can make calls but i can't hear anything.
My current distribution is Centos 7 Release 3.10.0-957.5.1.el7.x86_64