title: Received Facebook error response of type OAuthException: (#100) No matching user found (code 100, subcode 2018001)
body: <p>Im using restfb api for connecting facebook client
  and im trying to send message to facebook user(recipient) from facebook Page.</p>
  
  <p>But it is throwing error:
  Received Facebook error response of type OAuthException: (#100) No matching user found (code 100, subcode 2018001)</p>
  
  <p>and using this error code and subcode i found that recipient id i passed is wrong. recipient id i passed is generated by Graph API Explorer which returns as shown below and i used that id for recipient id 
  {
    "id": "XXXXXXXXXXXXXXXXXXXX",
    "name": "YYYYYYYYYYYYYYYYYYY"
  }</p>
  
  <p>so can anyone tell me how to generate recipient id of user.</p>