appsync subscription with arguments

I'm doing same as above for subscription but not getting response, It's only working with one argument room

mutation addMessage {
  addMessage(input: { 
  room: "45a87f5b-ef9e-41cd-9cd7-f3e2f4946d31", 
  receiver: "3cea9c02-1cf5-4248-8ebe-3580a7a47b8b" }) {
   id
   room
   receiver {
    id
    userName
   }
  }
 }

subscription roomMessage {
  roomMessage(room: "45a87f5b-ef9e-41cd-9cd7-f3e2f4946d31", 
  receiver: "3cea9c02-1cf5-4248-8ebe-3580a7a47b8b") {
    id
    room
    receiver {
      id
      userName
    }
  }
}

Subscriptions require the parameter you're filtering on to be in the response of the mutation. Could you try updating your mutation to this?

mutation mut{
  testSubMutation(param:"123") {
    param
  }
}