Why forms authentication fails in my code?

See more:

C#

ASP.NET

forms

authentication

i am using sitefinity and have added a login controller inside a sitefinity page(login).

When the login controller validates everytime, it fails throwing invalid credentials.

CODE:

public void Login_click(object sender, EventArgs e)
 {
     if (FormsAuthentication.Authenticate(txtUserName.Text, txtPassword.Text))
     {
         lblStatus.Text = ("Welcome " + txtUserName.Text);
         FormsAuthentication.RedirectFromLoginPage(txtUserName.Text, true);
     }
     else
     {
         lblStatus.Text = "Invalid credential.Please enter valid credentials.";
     }

 }

Is there any changes required in web.config file?

<location path="~/login">
   <system.web>
     <authorization>
       <allow users="*"/>
     </authorization>
     <compilation targetFramework="4.5"/>
   </system.web>
 </location>

 <system.web>
   <authentication mode="Forms">
       <forms name=".ASPXAUTH" loginUrl="~/login" >
         <credentials passwordFormat="Clear">
           <user name="kaplanuser" password="kaplan123"/>
           <user name="user1" password="pass123"/>
         </credentials>
       </forms>
     </authentication>
 </system.web>

What I have tried:

i commented

<authentication mode="None" /> and <remove name="FormsAuthentication" />

which i doubted made authentication to fail.