Hi, I am struggling  in integration. I have created a code and the response is internal server err.  please can anybody tell me what I have done wrong? I'm new to integration. my requirement is I have to create a javascript button. when I am clicking the button should send a request to Api and response should be updated Course Ids. How can I achieve that. I have  referred some posts but I didn't able to find what i have done wrong.
 my code.

global with sharing class CreateCourseInMoodle 
{
    public static final String token = PROFG_LMS_Setting__c.getValues('LMS_WS_Token').Value__c;
    public static final string categoryid = PROFG_LMS_Setting__c.getValues('BE_CategoryId').Value__c;
    public static final String endPoint = PROFG_LMS_Setting__c.getValues('LMS_EndPoint').value__c ;
    webservice static string requestMoodleCourse(String courseId)
    {
        system.debug('Ids'+courseId);
       List< Moodle_course__c> course = ((MoodleCoursesSelector_PG) Application_PG.selector.newInstance(Moodle_Course__c.SObjectType)).selectById(new Set<Id> {courseId});
        Map<String, String> inputsForCourse = new Map<String, String>();
        inputsForCourse.put('wstoken ', token);
        inputsForCourse.put('moodlewsrestformat', 'json');
        inputsForCourse.put('wsfunction','core_course_create_courses');
        inputsForCourse.put('courses[0][fullname]',course[0].Name);
        inputsForCourse.put('courses[0][shortname]',course[0].Name);
        inputsForCourse.put('courses[0][categoryid]', categoryid);
        inputsForCourse.put('courses[0][idnumber]',courseId);
        inputsForCourse.put('courses[0][summary]', course[0].Description__c);
        inputsForCourse.put('courses[0][summaryformat]','1');
        inputsForCourse.put('courses[0][format]','topics');
        inputsForCourse.put('courses[0][showgrades]','0');
        inputsForCourse.put('courses[0][newsitems]','0');
        inputsForCourse.put('courses[0][numsections]','2');
        inputsForCourse.put('courses[0][maxbytes]','2');
        inputsForCourse.put('courses[0][showreports]','0');
        inputsForCourse.put('courses[0][visible]','1');
        inputsForCourse.put('courses[0][hiddensections]','0');
        inputsForCourse.put('courses[0][enablecompletion]','1');
        inputsForCourse.put('courses[0][lang]','en');
        inputsForCourse.put('courses[0][groupmode]','0');
        inputsForCourse.put('courses[0][groupmodeforce]','0');
        inputsForCourse.put('courses[0][defaultgroupingid]','0');
        inputsForCourse.put('courses[0][customfields][0][shortname]','Country');
        inputsForCourse.put('courses[0][customfields][0][value]',course[0].Country__c);
        system.debug('mapOfcourse '+inputsForCourse);
        
        
        Http http = new Http();
        HttpRequest request = new HttpRequest();
        request.setEndpoint(endPoint);
        system.debug('endpoint'+endPoint);
        request.setMethod('GET');
        HttpResponse response = http.send(request);
          
        response = http.send(request);
        System.debug(response.getStatus());
        System.debug(response.getBody());
        if(response.getStatusCode() == 200)
        {
            system.debug('Success');
        }else
        {
            system.debug('Failure');
        }
        return response.getStatus();
    }
}