IronMQ won't send any "unknown" requests. If your endpoint doesn't return a 200, the push queue will keep retrying the message until it either a) receives a 200, or b) fails the "max_retries" number of times.
Also per Featilion's answer, check the multicast/unicast/subscriber setup as well. If you are getting requests to those other endpoints then there's something up with your subscriber setup.
Feel free to jump into live chat if you don't figure out your answer rather quickly.