public class TestBase extends HelperMethods {

    protected static final Logger LOGGER = Logger.getLogger(TestBase.class.getName());
    protected final Faker faker = new Faker();
    protected WebDriver driver;
    protected WebDriverWait wait;
    protected DashboardPage dashboard;

    @BeforeMethod
    @Parameters({"url"})
    public void setup(String url) {
        driver = Driver.get(); // Initialize the driver
        wait = new WebDriverWait(driver, Duration.ofSeconds(10));
        driver.manage().window().maximize();
        driver.get(url);
        dashboard = new DashboardPage();
    }

    @AfterMethod
    public void logOut() {
        try {
            dashboard.logout(); // Ensure the driver session is valid before logging out
        } catch (NoSuchSessionException e) {
            LOGGER.warning("WebDriver session is already closed: " + e.getMessage());
        }
    }

    
    @AfterClass
    public void tearDown() {
        Driver.closeDriver(); // Close the driver session
    }

}


public class TestBaseCustomer extends TestBase {

    protected LoginPage loginPage = new LoginPage();

    @BeforeMethod
    protected void setup() {
        loginPage.login(Credentials.User1, getDirectPageCode());
    }
}

public class ReceiptSearch extends TestBaseCustomer {

    private ReceiptSearchPage belegSuchen = new ReceiptSearchPage ();

    @Test
    public void test1() {...}

}

public class inventoryAccountDisplay extends TestBaseCustomer {

    private InventoryAccountDisplayPage inventoryaccount = new InventoryAccountDisplayPage();

    @Test
    public void test1() {...}

}


<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd">
<suite name="Suite">
    <test name="Customer XYZ">
        <parameter name="url" value="https://customerXYZ.com"/>
        <classes>
            <class name="ABC.tests.customerXYZ.accounting.ReceiptSearch "/>
            <class name="ABC.tests.customerXYZ.accounting.inventoryAccountDisplay "/>
        </classes>
    </test>
    
    <!-- More tests can be added similarly -->
</suite>

When I run my test cases from testng.xml, the first class runs perfectly fine. However, when it moves to the second one, the login throws a NoSuchSessionException: Session ID is null. Using WebDriver after calling quit()?. When I debug, I can log in and see that the driver is not null; it holds a ChromeDriver instance. The website is open, but the login data cannot be entered, and I get the NoSuchSessionException. Where is the problem?