Form authentication for . NET sites using Perl - forms

Question

We are new in Perl scripting and we wanted to pass through a .NET site authentication.
We have an existing code for authentication specific for Sharepoint sites, code snippet below:
my $ua = new LWP::UserAgent('keep_alive' => '1');
print "$url \n";
$ua->credentials("$uname", "$pwd");
my $response =$ua->get($url);
my $cde = $response->code();
We wanted to customize the code so that it will work specific for .NET sites authentication. We used WWW::Mechanize, see code snippet below:
my $mech = WWW::Mechanize->new();
$mech->cookie_jar(HTTP::Cookies->new());
$mech->get($url);
$mech->form_name('Login');
$mech->field("UserName", $username);
$mech->field("Password", $password);
$mech->click();
But when the program is run, an error is shown: "There is no form named 'Login' in sample.pl". Any thoughts on how to authenticate forms specific for .NET sites?
Adding: HTML form code snippet...
<div id="loginArea">
<div id="loginMessage" class="groupMargin">Sign in with your account</div>
<form method="post" id="Login" autocomplete="off" novalidate="novalidate" onkeypress="if (event && event.keyCode
== 13) Login.submitLoginRequest();" action="">
<div id="formsAuthenticationArea">
<div id="userNameArea">
<input id="userNameInput" name="UserName" type="email" value="" tabindex="1" class="text fullWidth" spellcheck="false" placeholder="Username" autocomplete="off">
</div>
<div id="passwordArea">
<input id="passwordInput" name="Password" type="password" tabindex="2" class="text fullWidth" placeholder="Password" autocomplete="off">
</div>
<div id="kmsiArea" style="display:none">
<input type="checkbox" name="Kmsi" id="kmsiInput" value="true" tabindex="3">
<label for="kmsiInput">Keep me signed in</label>
</div>
<div id="submissionArea" class="submitMargin">
<span id="submitButton" class="submit" tabindex="4" onkeypress="if (event && event.keyCode == 32) Login.submitLoginRequest();" onclick="return Login.submitLoginRequest();">Sign in</span>
</div>
</div>
</form>
</div>

Answer 1

Usually this code works for .NET sites:
$mech->submit_form(
with_fields => {
login => "somelogin",
pass => "somepass",
},
button => "submit_button_name",
);
But you have weird error message: you're selecting "Login" form but $mech searching for "loginForm"... Can you show actual form's HTML?
Also there is no need to do $mech->cookie_jar(...) because $mech do this by default.
UPDATE
Try this code (Login is id of your form but not the name):
$mech->submit_form(
with_fields => {
UserName => "somelogin",
Password => "somepass",
},
);