MR 816 routing issues

Hello all I hope everyone is in fine health and doing well. I’d like to ask a question. I am new to using the mr 816 and cubase 6. I connected my microphone into input 1 to do some test monitoring in the headphones and I received signal.I then switched and made my signal stereo on input one routing to tracks 1 and 2 with the mic signal. I am able to see it clearly and hear my vocal input fine. Next I connected my keyboard to inputs 3 & 4 on the back of the unit. Then I selected inputs 3 & 4 and went to quick connect for 3 & 4 and the light blinked.However after the light blinked and I attempted to arm the track in the input routing in cubase, I’m not getting any audio outputs. My tracks selection in 3 & 4 is just like my track selection in 1 and 2 but the audio isn’t working the same. Any ideas on what I am doing wrong?