TypeError: Cannot read property ‘_psychoJS’ of undefined

URL of experiment: Pavlovia

Description of the problem:
When running an online pliot, the following errors appear.
I’m looking for a way to solve this. Help me!
‘TypeError: Cannot read property ‘_psychoJS’ of undefined’

Begin Experiment :
background_sound = sound.Sound(‘english.wav’)

Begin Routine :
if trials.thisN == 0:

End Routine :
if trials.thisN == 15:

I always set up sounds using Builder components. Set the volume to 0 for the original component then setVoume(1) before playing it in code.