How to solve audio problem

Hello dear,

I am using Google Chrome but not generate audio call. When I using Mozilla Firefox then call is working fine but can’t here sound .

Install Ubuntu 16.04 and rocket chat server version 1.0.2
I am using installation process below link

Another I am install windows apps but can’t generate audio call to another. How to solve this problem. Please help me any one.

Advanced Thanks.
Alamin