Not able to create object of ExtentReports

I am new to extent reporting. I am using Selenium Webdriver and want to use Extent reports with it.

But my code is not able to create ExtentReport object.

package com.code.draft;

import org.openqa.selenium.WebDriver;
import org.openqa.selenium.firefox.FirefoxDriver;

import com.relevantcodes.extentreports.ExtentReports;
import com.relevantcodes.extentreports.ExtentTest;
import com.relevantcodes.extentreports.LogStatus;

public class TestReport {



    ExtentReports reports;
    ExtentTest logger; 
    WebDriver driver;

    public void start(){        
        reports = new ExtentReports("C:\User\Test\Report\Report.html"); //Exception at this line reports object = null
        driver = new FirefoxDriver();
        driver.get("http://www.google.com");
        logger = reports.startTest("Verify Title");
        logger.log(LogStatus.INFO, "Starting Browser");
        reports.endTest(logger);
    }

    public static void main(String[] args) {
        TestReport report = new TestReport();
        report.start();
    }


}

The above code is giving exception as :

Exception in thread "main" java.lang.NoSuchFieldError: VERSION_2_3_23
    at com.relevantcodes.extentreports.HTMLReporter.start(HTMLReporter.java:76)
    at com.relevantcodes.extentreports.Report.attach(Report.java:314)
    at com.relevantcodes.extentreports.ExtentReports.<init>(ExtentReports.java:85)
    at com.relevantcodes.extentreports.ExtentReports.<init>(ExtentReports.java:419)
    at com.code.draft.TestReport.start(TestReport.java:19)
    at com.code.draft.TestReport.main(TestReport.java:29)

Using the below configuration :

<dependency>
            <groupId>com.relevantcodes</groupId>
            <artifactId>extentreports</artifactId>
            <version>2.41.2</version>
</dependency>

if anyone have idea. Please help.

Answer

I tested your code. It shows no exception at my end. But to get your HTML report you need to flush using reports.flush() just before reports.endTest(logger);.