But the apify api sometimes didn't work correctly, I mean sometimes the result is zero. what is the reason, I just guess the reason is rate limitation, I am not sure Please Help me out, Thank you

Someone will reply to you shortly. In the meantime, this might help:

hey, I'm not sure I understand the question. What do you mean by Apify API, did you create your own actor or are you using something from the store?

Try adding error logging in your code to better understand where things are going wrong. You can also view these logs on the Apify platform.