Web services

Hi, I'm trying to delvelop a system which consumes some of the Moodle's web services. In this system there are 3 steps related with the Moodle's web service which are:

-Get all the courses belong to Instructor
-Get all the assignments belong to selected course
-After editing the assignment, update it with the latest one.

I easily implemented first two of them but updating an assignment is the problematic part. When I use local_o365_update_onenoteassignment function, it returns "Invalid Parameter Value Detected" error although parameters are correct. Here is my code below. I appreciate it if you help me.

       
        String token = "adcd621f420dfc3000f106a6ebcebccb";
        String domainName = "http://localhost:81/moodle";
        String functionName = "local_o365_update_onenoteassignment";
       
        String urlParameters =  "data[coursemodule]= "+CurrentAssignment.getCourseModuleID()+
                                "&data[course]="+Course.getCurrentCourse().getCourseId()+
                                "&data[name]="+CurrentAssignment.getAssignmentName()+
                                "&data[intro]="+CurrentAssignment.getIntro()+
                                "&data[section]= 0"+
                                "&data[visible]= 1";
                                
        String restformat = "&moodlewsrestformat=json"; 

        String serverurl = domainName + "/webservice/rest/server.php" + "?wstoken=" + token + "&wsfunction=" + functionName;
        HttpURLConnection con = (HttpURLConnection) new URL(serverurl).openConnection();
        con.setRequestMethod("POST");
        con.setRequestProperty("Content-Type",
        "application/x-www-form-urlencoded");
        con.setRequestProperty("Content-Language", "en-US");
        con.setDoOutput(true);
        con.setUseCaches (false);
        con.setDoInput(true);
        DataOutputStream wr = new DataOutputStream (
        con.getOutputStream ());
        wr.writeBytes (urlParameters);

        wr.flush ();
        wr.close ();