Why does the modal window disappear at 1100px resolution?

Question

Bootstrap

I've been scratching my head for a day now!
Well, the essence is actually clear, with a resolution of less than 1100 px, the modal window simply disappears. Including mobile phones, etc.
Accordingly, I rummaged through the entire Internet, nothing.

<div class="modal fade" id="modal01" tabindex="-1" role="dialog"
                             aria-labelledby="exampleModalLabel" aria-hidden="true">
                            <div class="modal-dialog" role="document">
                                <div class="modal-content">
                                    <div class="modal-body">
                                        <div class="container">
                                            <div class="row">
                                                <img src="images/logo.png" class="logo mx-auto mb-3">
                                            </div>
                                            <div class="caption text-center">Оповестить<br> о запуске проекта</div>
                                            <form action="index.html" method="post">
                                                <div class="row">
                                                    <p class="push text-uppercase mx-auto">Электронная почта</p>
                                                </div>
                                                <div class="form-group">
                                                    <input type="email" placeholder="[email protected]" autocomplete="off"
                                                           required class="form-control text-center">
                                                </div>
                                                <div class="row">
                                                    <p class="push text-uppercase mx-auto">телефон</p>
                                                </div>
                                                <div class="form-group">
                                                    <input type="phone" placeholder="+7 (___) ___ - __ - __"
                                                           autocomplete="off" required class="form-control text-center">
                                                </div>
                                                <div class="row">
                                                    <p class="push text-uppercase mx-auto">Удобный способ связи</p>
                                                </div>
                                                <div class="form-group">
                                                    <select class="form-control sel">
                                                        <option value="" disabled selected>Выберите</option>
                                                    </select>
                                                </div>
                                                <div class="row">
                                                    <p class="push text-uppercase mx-auto">whatsapp</p>
                                                </div>
                                                <div class="form-group">
                                                    <input type="phone" autocomplete="off" required
                                                           class="form-control text-center">
                                                </div>
                                            </form>
                                            <div class="container">
                                                <div class="row">
                                                    <p class="push mx-auto text-center">Нажимая кнопку “Оповестить
                                                        меня”, вы даете свое<br> согласие на обработку ваших
                                                        персональных данных.</p>
                                                </div>
                                            </div>
                                            <div class="row">
                                                <div class="button-auth button-auth-green1 mx-auto">
                                                    <button>Оповестить меня</button>
                                                </div>
                                            </div>
                                        </div>
                                    </div>
                                </div>
                            </div>
                        </div>

Answer 1

I didn’t climb into the bootstrap with scripts, I didn’t overlap anything, everything seems to be transparent, but it just disappears by 1100 px down, that is, when you press the button, just a darkened area appears. (the same div)
and my modal window is not there. I've tried looking everywhere, it's just not there)