Tan pronto como muevo mi aplicación Laravel de MySQL a pSQL. Seguí recibiendo este error.

El contenido de Response debe ser una cadena o un objeto que implemente __toString (), dado "booleano".

Tengo una API que supone devolver mi promoción

http: // localhost: 8888 / api / promotion / 1

public function id($id){
    $promotion = Promotion::find($id);
    dd($promotion); //I got something here
    return $promotion;
}

Solía devolver mi promoción, ahora devuelve un error.

dd ($ promoción);

I got 

Promotion {#410 ▼
  #table: "promotions"
  #connection: null
  #primaryKey: "id"
  #perPage: 15
  +incrementing: true
  +timestamps: true
  #attributes: array:16 [▼
    "id" => 1
    "cpe_mac" => "000D6721A5EE"
    "name" => "qwrqwer"
    "type" => "img_path"
    "status" => "Active"
    "heading_text" => "qwerq"
    "body_text" => "werqwerqw"
    "img" => stream resource @244 ▶}
    "img_path" => "/images/promotion/1/promotion.png"
    "video_url" => ""
    "video_path" => ""
    "account_id" => 1001
    "img_url" => ""
    "footer_text" => "qwerqwerre"
    "created_at" => "2016-08-04 10:53:57"
    "updated_at" => "2016-08-04 10:53:59"
  ]
  #original: array:16 [▶]
  #relations: []
  #hidden: []
  #visible: []
  #appends: []
  #fillable: []
  #guarded: array:1 [▶]
  #dates: []
  #dateFormat: null
  #casts: []
  #touches: []
  #observables: []
  #with: []
  #morphClass: null
  +exists: true
  +wasRecentlyCreated: false
}

Contenido

__ ¡Cualquier sugerencia / sugerencia sobre esto será de gran ayuda!