"JSON.parse: unexpected character at line 1 column 1 of the JSON data" on angular – Laravel

In a register component. I can register a new user but I got a json.parse error. I tested the component with postman and it is ok. but I dont know why the json is bad.

register.component.ts

this.user = this.forma.value;
        this._userService.signup(this.user).subscribe(
        {
          next: (response) =>
          {
            console.log(response);
            console.log(this.forma);
  
            if(response.status == "success")
            {
              this.status = response.status;
              this.forma.reset();
            }
            else 
            {
              this.status = 'error';
              console.log("error status", this.status);
              
            }
            
            },
            error: (error) =>
            {
              console.log(<any>error);
            }
        
          });`enter code here`

user.service.ts

  signup(user, gettoken = null):Observable<any>
  {
      if(gettoken != null)
      {
        user.gettoken = 'true';
      }

      let json = JSON.stringify(user);
      let params = 'json='+json; 
      console.log(params);
      let headers = new HttpHeaders().set('Content-Type', 'application/x-www-form-urlencoded');
      return this._http.post(this.url+'login', params, {headers:headers});     
  }

I forgot to say that the jwt token is added to the json

{
  "error": {},
  "text": "array(2) {n  ["email"]=>n  string(17) "[email protected]"n  ["password"]=>n  string(8) "password"n}n"eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJzdWIiOjUsImVtYWlsIjoibWFydGFAZXhhbXBsZS5jb20iLCJuYW1lIjoibWFydGEiLCJzdXJuYW1lIjoibWVqaWEiLCJpYXQiOjE2NzM4NjIxODgsImV4cCI6MTY3NDQ2Njk4OH0.aGIE_5peskBjbTSA3GSaHJukq0yL_EpSaOIMOE8JUzg""
}

this is the method on the backend with laravel

 public function login(Request $request)
    {

        $jwtAuth = new JwtAuth();

        // recibir datos por post
        $json = $request->input('json', null);
        $params = json_decode($json);
        $params_array = json_decode($json, true);
        var_dump($params_array);


        // validar esos datos
        $validate = Validator::make($params_array, [

            'email'   =>    'required|email',  
            'password'=>    'required'
        ]);

        if($validate->fails())
        {
            $signup = array(

                'status' => 'error',
                'code' => 404,
                'message' => 'el usuario no se ha podido identificar',
                'errors' =>$validate->errors()
            );
        
            
        }
        else
        {
            // cifrar la password
            $pwd = hash('sha256', $params->password);

             // devolver token o datos
             $signup =  $jwtAuth->signup($params->email, $pwd);

             if(!empty($params->gettoken))
             {
                $signup =  $jwtAuth->signup($params->email, $pwd, true);

             }

        }

        return response()->json($signup, 200);
    
    }