ERRO: Object reference not set to an instance of an object.

[Karina Campanharo]

Hey guys. I'm creating automated tests with Selenium, C# and Specflow. I need to create several .features files, object page files and steps files. However, when I create several test files I receive the error below, does anyone know how to resolve it?

Message: 
System.NullReferenceException : Object reference not set to an instance of an object.

  Stack Trace: 
SearchPage.Pesquisa(String name) line 23
FeatureEmQueOUsuarioFazUmaPesquisaNoLinkedinStepDefinitions.WhenQuandoEuInsiroONomeDaPesquisa() line 17
BindingInvoker.InvokeBinding(IBinding binding, IContextManager contextManager, Object[] arguments, ITestTracer testTracer, TimeSpan& duration)
TestExecutionEngine.ExecuteStepMatch(BindingMatch match, Object[] arguments, TimeSpan& duration)
TestExecutionEngine.ExecuteStep(IContextManager contextManager, StepInstance stepInstance)
TestExecutionEngine.OnAfterLastStep()
TestRunner.CollectScenarioErrors()
FeatureEmQueOUsuarioFazUmaPesquisaNoLinkedinFeature.ScenarioCleanup()
FeatureEmQueOUsuarioFazUmaPesquisaNoLinkedinFeature.RealizarUmaPesquisaNoLinkedIn() line 9

  Standard Output: 
Given Eu estou Logado na Página do Linkedin
-> done: LoginPageStepDefinitions.GivenEuAcesseiAPaginaDeLogin() (2.8s)
When Quando eu insiro o nome da pesquisa
-> error: Object reference not set to an instance of an object. (0.1s)
Then Exibe vários resultados
-> skipped because of previous errors

below is my code: searchpage.cs

using OpenQA.Selenium.Support.UI;
using OpenQA.Selenium;
using MeuProjeto.PageObjects;
using System;


namespace MeuProjeto.PageObjects
{
    public class SearchPage : BaseLogin

    {

        private IWebDriver Driver;
        private WebDriverWait Wait;

        private IWebElement fieldSearch => Driver.FindElement(By.XPath("//input[@id='username']"));

        private IWebElement responseOption => Driver.FindElement(By.XPath("//a[contains(text(),'Sign in')]"));


        public void Pesquisa(String name)
        {
            Driver.Manage().Timeouts().ImplicitWait = TimeSpan.FromSeconds(5);
            fieldSearch.SendKeys(name);
        }

        public void Response()
        {
            Driver.Manage().Timeouts().ImplicitWait = TimeSpan.FromSeconds(5);
            responseOption.Clear();
        }




    }
}

below is my code: FeatureEmQueOUsuarioFazUmaPesquisaNoLinkedinStepDefinitions

using MeuProjeto.PageObjects;
using System;
using TechTalk.SpecFlow;

namespace MeuProjeto.StepDefinitions
{
    [Binding]
    public class FeatureEmQueOUsuarioFazUmaPesquisaNoLinkedinStepDefinitions

    {
        SearchPage searchPage  = new SearchPage();


        [When(@"Quando eu insiro o nome da pesquisa")]
        public void WhenQuandoEuInsiroONomeDaPesquisa()
        {
            searchPage.Pesquisa("MICHELE");
        }

        [Then(@"Exibe vários resultados")]
        public void ThenExibeVariosResultados()
        {
            searchPage.Response();
        }
    }
}