2 subs 1 cutting out

Hi im new here with a frustrating problem. First off I have a Re audio dts 1000.1 amp hooked to 2 powerbass s12 s That are dual 4 ohms each but I have it wired to the amp at 1 ohm to give me 400 watts per sub rms. The problem im having is the system played real good the whole first day it was...