I got a 429 error for too many requests. I waited for about 20-30 minutes to resubmit the request. It is for just one symbol, NGK2^0. I keep getting the same error
Perhaps you've exhausted your daily download limit? This is just a guess. Try again submitting the request after midnight (when the daily quota is renewed). If the issue persists it would be helpful to see the exact request you're sending and the response you're getting including the full error message.