(before i start i am completely new to this kind of thing and usually just use computer speakers)

I am playing a party tomorrow and went and rented a pair of JBL Eon15 G2's today. I initially hooked up each speaker with a 1/4" cable to the main output 1 and 2 on my kontrol s4. The issue that i am having is that only one of the speakers will work and only when plugged into the 1 output, but none of them on the 2 output. I dont know if something is wrong with the kontrol itself or im just such a noob that i am missing something haha, i have to have this fixed tonight so if anybody could help me out i would greatly appreciate it!