Issue on plotting Phase Noise curve

Hi all,

I am using Virtuoso Custom IC design Environment version ICADVM20.1-64b.500.21.

I ran PSS and PNOISE to characterize ring oscillator's phase noise. PSS and PNOISE setup is shown below.

Simulation completed successfully, but it failed to plot "Phase Noise", but "output noise" for saved net can be plot. 

The error message is listed below:

*Error* difference: can't handle (srrWave:0x905e0040 - nil)
<<< Stack Trace >>>
(... in unknown ...)
(... in phaseNoise ...)
(... in pn ...)
pn('pnoise)
(... in _drplOscCornerFreqLabel ...)
(... in unknown ...)
(... in _drplSubmitPlot ...)
(... in _drplPlotButtonCB ...)
_drplPlotButtonCB(asidrplPlotForm51)
(... in geEcStartCmd ...)
(... in astiStartSelect ...)
(... in _drplInvoke ...)
(... in asiDirectPlotResultsMenuCB ...)
(... in sevDirectPlot ...)
sevDirectPlot('sevSession52 'asiDirectPlotResultsMenuCB)
(... in unknown ...)
(... in unknown ...)
(... in _axlADEToolDoWithTemporaryDataDir ...)
(... in unknown ...)
(... in _axlInvokeOutputActionMethod (axlToolAdeAbstract t t) ...)
(... in _axlInvokeOutputAction ...)
_axlInvokeOutputAction("fnxSession0" "tran_8ph_5ff" "/nfs/site/disks/adhdk.work.6/x78a_work/io/yutaoliu/gpsio/simulation/serdesrxclk_adhdk_sim/tb_x78serdesrxclk_clkgen_ro_top/maestro_kvco/results/maestro/Interactive.32/1/tran_8ph_5ff" "sevDirectPlot('sevSession52 'asiDirectPlotResultsMenuCB)" ?history ... )

How can I resolve this issue? Or it there any workaround I can get Phase noise (dBc/Hz)?

Thanks and regards,

Yutao