microphone hiss when rmx2 mic button pressed!

i been having this problem and can not find a solution anywhere. using rmx2 virtual dj pro 7 and either a wired mic shure pg48 with 1/4" or my wireless line6 xv-v30 with xlr cable. as soon as i press the mic button on the rmx2 an incredible amount of line hiss pops in even without a mic inputed. set to line on back of unit. in the rmx control panel input 1-2 set to mic. how can i fix this?