Error: No input file specified when sending email

[Maher_Nabeel]

I have html a page that takes the email details and pass it to semail.php but whenever I try it this error appears No input file specified.

This is the html form:

 

<form method="POST" sourceindex="44" action="semail.php" name="form1" onSubmit="return validate_form ( );">
        <p>
          <label>Your name:<br>
            <input sourceindex="47" name="mail_name" class="text_field" type="text">
          </label>
        </p>
        <p>
          <label>Your e-mail:<br>
            <input sourceindex="51" name="mail_email" 
class="text_field" type="text">
          </label>
        </p>
        <p>
          <label>Message:<br>
            <textarea sourceindex="55" name="mail_msg" cols="45" 
rows="5" class="text_area"></textarea>
          </label>
        </p>
        <input name="B1" type="submit" class="form_button" value="" />
      </form>

 

and this is the php code:

 <?php
$mail_to ="someEmail@hotmail.com";
$mail_subject = "Message From a Customer";
$mail_body ="Name of the Coustomer: ".$_POST['mail_name']."\n";
$mail_body .= "E-Mail Of the Coustomer: ".$_POST['mail_email']."\n";
$mail_body .= "The Message: ".$_POST['mail_msg']."\n";
if(mail($mail_to, $mail_subject, $mail_body))
echo "Thanks for your Message";
else 
echo "Failed to send the e-mail"
 ?>

any suggestions what is causing this weird error ? 

[Maher_Nabeel]

I just discovered that no php file is running. why ? and how to solve it ?

[DFulg]

This error indicates that semail.php either does not exist, or is not in the same directory as the file that contains the HTML form.

[priyankagound]

To first check and verify that PHP is running and available with the present Web hosting company, create a file called check_server.php and insert the following code:

<?php

// Show all information, defaults to INFO_ALL
phpinfo();

// Show just the module information.
// phpinfo( yields identical results.
phpinfo(INFO_MODULES);

?>

If successful, you will see your server information and configurations. It will also show the path to mail.