I submitted my facebook messenger bot for app review and the rejection reason was "received no response".
I've tested my bot from my own account and some other testers that I added to my facebook app for testing.
However, when I try to test using the default Open Graph Test User
I don't get any response. The Send Message API fails with error:
{"error": {"message":"(#100) No matching user found", "type":"OAuthException", ...}}
What am I doing wrong here? How can I send message to test users using the Send/Receive message API?