I am playing a UGX map and no matter what gun my partner on WAW Zombies lan has, they make no sound. I hear my gun, my partner here's their gun, but we don't hear eachothers. How can I fix this!

I hear it when their character says something, and I can hear every other interaction, but just not guns.
I can also hear my partners bullets hit objects, but not the gun!!
 please help me!