question about ADS budget simulation

hello !
i am using ADS2005A budget analysis.but when i set a LNA as subnetwork,i simulated the toplevel schematic ,there is a wrong about S21 .it says s21 is too small.But I simulated the LNA in the subnetwork ,the gain is 15dB.can you please tell me why?

can u upload the project to check it

Khouly

Thanks! I have solved the problem.I set the frequency 2000_MHz not 2000 MHz!