No sound from Komplete Audio 6 with Sonar X1

Hi, I'm using Sonar X1 producer Expanded and I just bought the Komplete audio 6. When I plug in my synthesizer to the input 3/4, set audio IN to Komplete 3/4 at the track and master output to Komplete mains out, I can't hear any sound from the main output 1/2 to my speakers. I can see the signal at the meter at Sonar and the input signal at the Komplete audio 6 but no signal out. Need help from all of you.