Getting this error "Methods defined as TestMethod do not support Web service callouts"

I'm getting this error "Methods defined as TestMethod do not support Web service callouts" in Apex Scheduler Test class.  My code as below...

global class DailyFetchMSDynamicCRMLeads implements Schedulable {
    global void execute(SchedulableContext ctx) {
        MSDynamicCRMUtilityService msDynCRM = new MSDynamicCRMUtilityService();
        MSDynamicCRMUtilityService.GetLeadsFromMSDynamic();
    }
}

@isTest
public class DailyFetchMSDynamicCRMLeadsTest {
    @isTest
    static void TestDailyFetchMSDynamicCRMLeads(){//testmethod
        Test.startTest();
        Lead lObj = new Lead();
        lObj.FirstName = 'Test FirstName';
        lObj.LastName = 'Test LastName';
        lObj.Company = 'Test Company';
        insert lObj;
        // This test runs a scheduled job at midnight Sept. 3rd. 2022
        String CRON_EXP = '0 0 0 3 9 ? 2022';
        // Schedule the test job
        String jobId = System.schedule('DailyFetchMSDynamicCRMLeads', CRON_EXP, new DailyFetchMSDynamicCRMLeads());
        // Get the information from the CronTrigger API object 
        CronTrigger ct = [SELECT Id, CronExpression, TimesTriggered, NextFireTime FROM CronTrigger WHERE id = :jobId]; 
        // Verify the expressions are the same System.assertEquals(CRON_EXP, ct.CronExpression); 
        // Verify the job has not run 
        System.assertEquals(0, ct.TimesTriggered); 
        // Verify the next time the job will run 
        System.assertEquals('2022-09-03 00:00:00', String.valueOf(ct.NextFireTime));   
        Test.stopTest();        
    }
}