Output power at 0Hz ADS HB simulation

When you do HB simulation in ADS for amplifier or oscillator and it shows very high dBm at 0Hz ( in the spectral plot) along with the others, what does it mean?

0 Hz is DC.Your output has DC voltage..
That's why..

seems like my DC block capacitor at the output is not working the way it should..what could be the reason?