I have one big problem:
I've been working on a project and always gives me this error:
Warning: Cannot modify header information - headers already sent by (output started at C:\xampp\htdocs\output\index.php:60) in C:\xampp\htdocs\output\Login.php on line 40
I tried everything, but it does not work... I tried remove html and when I remove all html and remain only form to submit data then already works...
On line 60 in index.php have only <?php ...
On line 40 in Login.php have  header('Location: profile.php');
This is index.php file:
<?php
session_start();
error_reporting(E_ERROR | E_WARNING | E_PARSE);
require './Login.php';
?>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" lang="bg-BG" prefix="og: http://ogp.me/ns# fb: http://ogp.me/ns/fb#" itemscope itemtype="http://schema.org/Article">
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    </head>
    <body>
        <div class="lightbox_bg" id="lightbox_bg" style="display: none;"></div>
        <div class="box_bg1">
            <div class="lightbox_registration lightbox" style="display:none">
                <a href="#" class="lightbox_close"></a>
                <h1>text </h1>
                <p>text </p>
            </div>
            <div id="site">
                <a href="index.php" class="logo"></a>
                <ul class="topMenu">
                    <li><a class=" "  href="materialy/materialy.html">text</a></li>
                    <li><a class=" "  href="prirucka/index.php">text</a></li>
                    <li><a class=" showLightbox topRegistrace" rel=".lightbox_registration" href="#">Register</a></li>
                </ul>
                <div class="clearboth"></div>
                <form action="" method="post" id="frm-loginEmailForm">
                    <div class="clearboth"></div>
                    <div class="toplista">
                        <div class="label"><label for="frmloginEmailForm-email">e-mail </label>:</div>
                        <input type="text" class="textwhite" name="email" id="frmloginEmailForm-email" required="required" data-nette-rules="{op:':filled',msg:"\u041c\u043e\u043b\u044f, \u0432\u044a\u0432\u0435\u0434\u0435\u0442\u0435 e-mail \u0430\u0434\u0440\u0435\u0441\u044a\u0442, \u043a\u043e\u0439\u0442\u043e \u0441\u0442\u0435 \u043f\u043e\u0441\u043e\u0447\u0438\u043b\u0438 \u043f\u0440\u0438 \u0440\u0435\u0433\u0438\u0441\u0442\u0440\u0430\u0446\u0438\u044f\u0442\u0430. "},{op:':email',msg:"\u041c\u043e\u043b\u044f, \u0432\u044a\u0432\u0435\u0434\u0435\u0442\u0435 \u0432\u0430\u043b\u0438\u0434\u0435\u043d \u0435-mail \u0430\u0434\u0440\u0435\u0441.  "}" value="" />
                        <div class="label"><label for="frmloginEmailForm-password">Pass</label>:</div>
                        <input type="password" class="textwhite" name="password" id="frmloginEmailForm-password" required="required" data-nette-rules="{op:':filled',msg:"\u041c\u043e\u043b\u044f, \u0432\u044a\u0432\u0435\u0434\u0435\u0442\u0435 \u043f\u0430\u0440\u043e\u043b\u0430. "},{op:':minLength',msg:"\u0412\u044a\u0432\u0435\u043b\u0438 \u0441\u0442\u0435 \u0442\u0432\u044a\u0440\u0434\u0435 \u043a\u0440\u0430\u0442\u043a\u0430 \u043f\u0430\u0440\u043e\u043b\u0430. ",arg:2}" />
                        <input type="hidden" name="login" value="1">
                            <input type="submit" class="blackbutton" name="odeslat" id="frmloginEmailForm-odeslat" value="Login" />
                    </div>
                </form>
                <div id="hlasky" class="hide">text </div>
                <div id="obsah">
                    <div class="lightbox lightbox_medialni" style="display:none">
                        <a href="#" class="lightbox_close"></a>
                        <h1>text</h1>
                        <div>
                        </div>
                        <div class="clearleft"></div>
                    </div>
                    <div class="lightbox lightbox_dalsi" style="display:none">
                        <a href="#" class="lightbox_close"></a>
                        <h1>text</h1>
                        <div>
                        </div>
                        <div class="clearleft"></div>
                    </div>
                    <div class="box_content">
                    </div>
                </div>
            </div>
        </div>
        <?php
        if (isset($_POST['login']) && $_POST['login'] == 1) {
            Login::LoginUser($_POST['email'], $_POST['password']);
        }
        ?>
    </body>
</html>
 
     
    