WHMCS Module not creating

Whenever someone gets a plan, it doesn’t process anything. Doesn’t make an account for the user nor adds the website to the DNS zone. I enabled API for the admin account, verified it’s fully working. I’m not sure if this might help but when the user goes to manage his plan the sign in to control panel area gives this error:
{“userID”: 0, “loginStatus”: 0, “error_message”: “Administrator matching query does not exist.”}

I’ve same problem can anyone help to solve it?
Thnks