pss P1dB simulation not convergent

Hi,

I want to simulate Mixer chain P1dB by cadence PSS. It is supposed at 5dBm(input P1dB). The whole chain is consisted of mixer, LPF, two stage IF amplifier. The total voltage gain is 23 dB. The problem is when I swept PSS input power up to 0 dBm, it could't converge. Anyone knows how I can make it convergent and get the P1dB point I want?

Thanks