Steinberg ur44 Line5/6 Problem

so Ive been using all 6 inputs for some time now., using input 5 and 6 via a mixer with the preamp. recorded a nice clean drum session using 6 mics 3 days ago, today I went to start a new project using the 6 inputs and my 5 and 6 inputs is just giving me a no signal with a pop sound that happens consecutively every 10 seconds, only when I enable the monitoring function., I know its coming from the UR44 because I unplugged the mixer and its still doing it., again only when the monitor button is active., no audio signals record in these 2 inputs, while 1-4 works fine.,

is my ur44 toast?