Problem processing JSON generated by JSONcpp

I am building the following JSON using JsonCpp in a C++ app:

PUT http://localhost/AvionBiometricRestService/api/Identify/ HTTP/1.1
Accept: */*
Content-Type: application/json
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0;Windows NT 5.1)
Host: localhost
Content-Length: 2738
Connection: Keep-Alive
Pragma: no-cache

{ 
       " b i r d a t a "   :   " I B Q 3 A A Q B Z A I A A A B A N w A E A d 8 H C B o M J h k A A A A A A D c A B A E A A A A A A A A A A A A A A A A A A A A A A A A A A A g D A A B r \ r \ n e H M X C R 2 R s D K h p n J w W U m U T h c n I k e J g 3 K 1 t O f 0 5 p I l o 6 D O O d 0 A E Q O g m u Q O X Z K N p x v x m 1 R v Y U 5 / 4 a w 5 \ r \ n J o D I h N l 1 G V 7 d M j v v i O u l g a q c z L E k G 4 5 L Z C 9 k N E 3 o 9 B d i Y L f E d b L 4 1 f R d Z 8 G 9 Z 1 b 7 6 6 h 7 c l r D a 1 J u \ r \ n M U K v D D 3 g R h 0 B K 5 I o Y e L B D e f V v g s i u O Y v X s c R H C 2 E l D B s M 8 j C B h T G u 7 B E 1 n 3 g d O W L O r G v j A P T 2 u s 1 \ r \ n w L Q 7 j w Q V Z 7 D m 9 G t T q C K p f x S w m Z M a 3 F b T e j O T M + h h V O H N 1 i + Q n n 4 d 1 n X p n / G X f j n T x A 6 X l E + I q v B V \ r \ n L b 4 M / j Q U K l H y y 4 F H e U 3 s Y V h u / A j T P 2 U O 8 c + R 9 U 7 f d 1 G n m A 0 6 f 0 t o y w W h d 4 3 d h E n O 7 j Y x z 1 2 T a + a G \ r \ n 8 j y 7 l 4 Z B I q v p X R H Q G y L S G m Z 0 R g C 2 k m k v P K 7 Q W O + Y Y i m I 9 7 f + 2 a y f e L V J Z z 5 + d a d x G V a w a x 5 f N d V b \ r \ n / z 8 d o N J r x Y T n k k G F k L J i s n z y A I Z C / l 0 z x b 3 / 8 l y h 3 + x q 0 9 l l 3 K r z I 9 i 9 a s P y A G O N c r v 7 k q O e B O Y b \ r \ n P 5 d A y 4 q 1 b T g 0 x R S 2 Q v E H 9 l G o 6 r T U 3 M d C K Q C o s 3 0 D F 9 n e x 8 V Q c f r w 8 2 g t t H x H b D S k j P 9 9 J w 1 9 s 2 + s \ r \ n M D u S 6 S 4 j y + s w 4 q m n t N 2 Q f c 1 r H F u q / I b w X i 6 Y Q 3 k A R 4 G N z 9 Z E A q f e 8 y j X + d 9 5 U Y 5 L 6 9 m t H l D m X T D G \ r \ n u r a w b W m + w 3 J I Q a 0 k I S E d g j B Z N o a 1 E j 4 T M L b i r u a j S i 3 2 G 1 9 z v a Q q / S / f 6 i B Q y o W i 7 D X a / U X V W w g V \ r \ n X v C N A C A / c n 8 K x 5 e N T 7 k v a O 3 I u G k E 6 f p M e + W U j H a 8 c Y L y x 7 X 1 r l E 8 p 2 4 l x S e Y U x Z J g x R s l W / 9 J M b M \ r \ n J 1 z V 9 D S E 7 6 5 N s X Y m 4 G V G r 4 w L v l 5 3 I 3 S i X D v A K z z l 9 J 5 W J Y r X 5 8 + l d a h u 5 k 0 t l u l e M A 9 A r d K d I Z 2 e \ r \ n m T R k U T t T U J I t K q n H N l Y y 2 F A D A 9 y L 9 4 0 o 6 7 e a G n 7 u r V D v a v L m w l v Y l Z 8 O j L b c C 0 2 v F J Y z G 0 M j G Z 6 v \ r \ n n H O F a Y T u N 6 4 D D 0 w s 3 u l 8 i 2 e d q N g 8 P / B N j H K U 2 V I f G t F F I w A A A A A = " , " e r r o r _ m e s s a g e "   :   t r u e , " e r r o r _ r e t u r n e d "   :   0 , " n u m b e r o f p e r s o n s r e t u r n e d "   :   0 , " p e r s o n i d s "   :   t r u e , " p r o d u c t o w n e r "   :   5 5 , " p r o d u c t t y p e "   :   2 6 0 , " s u b t y p e "   :   0 
 } 	 

The WebAPI model looks like this:

public class IdentifyModel
 {
        public int subtype { get; set; }
        public int productowner { get; set; }
        public int producttype { get; set; }
        public string birdata { get; set; }
        public string personids { get; set; }
        public int numberofpersonsreturned { get; set; }
        public string error_message { get; set; }
        public int error_returned { get; set; }
}

The request makes it to the controller method:

public IHttpActionResult  Put(IdentifyModel value)
{
    try
    {
           return Ok(value);
    }
    catch (Exception ex)
    {
       return BadRequest();
    }
}

However, the JSON is not getting parsed into the IdentifyModel as it is null

Am I missing a step?