I get errors in comparing a id and ss plot for fit percentage , it says the matrix is ill conditioned! what am i supposed to do now?

Warning: Model response could not be computed successfully for generating the comparison result. The model may be
ill-conditioned. 
> In idpack.compareResp (line 161)
  In iduis.plots.compare (line 37)
  In wavepack.waveform/draw (line 25)
  In wrfc.plot/draw (line 17)
  In wrfc.plot/init_listeners>LocalRefreshPlot (line 79)
  In compareplot>localCompare (line 337)
  In compareplot (line 167)
  In compare (line 200)