Unable to enter a string in the text box. It just opens the browser

I want to open the site www.flock.co and enter a email in the text field.However the program only opens the site and doesnt enter the email in the field.

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

public class FindByClassName {

    public static void main(String[] args) throws Exception {
        System.setProperty("webdriver.gecko.driver", "C:\\Automation\\geckodriver-v0.15.0-win64\\geckodriver.exe");
        WebDriver driver = new FirefoxDriver();
        driver.manage().window().maximize();
        driver.get("https://flock.co/");

        driver.findElement(By.className("_g-s-wrap")).sendKeys("farzan.s@flock.co");
    }

}

_g-s-wrap is the class of a container that includes more features (like the "Get Started" button). Use cssSelector to locate the <input> textbox

driver.findElement(By.cssSelector("[type='email']")).sendKeys("farzan.s@flock.co");