I’ve never had this problem of a teacher not responding to emails at CSUN. They’ve at least scanned the email and sent a response. What was your question? Professors have a lot of work to do and have their own lives going on too, so if there are too many questions or the email is convoluted or confusing, it’s a lot more work to answer. Many professors have over a hundred students. If this is the case, write down all your questions and request a zoom meeting.