Chuwi corebook pro laptop microphone not working intermittently

hi , we have purchase a Chuwi corebook pro last 3 weeks ago. My daughter has been using it on her online class ( google classroom ). She was using the laptop speaker to listen and talk to her teacher. However there are times that the teacher wont hear her voice because the mic is not working? it has been an intermittent issue sometimes it has mic sometimes it don’t have. hopefully you could help us.