Can you open flag.php?:
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/css/bootstrap.min.css">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">
<script src="https://code.jquery.com/jquery-3.5.1.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.0/dist/umd/popper.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/js/bootstrap.min.js"></script>

<div style="
    width: 30%;
    margin: 10% auto;">
<form method="post">
        <h2 class="text-center">Log in</h2>       
        <div class="form-group">
            <input type="text" name=uname id=uname class="form-control" placeholder="Username" required="required" data-keeper-lock-id="k-8eubxq41tdy">
        <keeper-lock class="focus-visible keeper-lock-disabled" tabindex="0" id="k-8eubxq41tdy" aria-label="Open Keeper Popup" role="button" style="background-image: url(&quot;chrome-extension://bfogiafebfohielmmehodmfbbebbbpei/images/ico-field-fill-lock-grey.svg&quot;) !important; background-size: 16px 16px !important; cursor: pointer !important; width: 16px !important; position: absolute !important; opacity: 0 !important; margin-top: auto !important; min-width: 16px !important; top: 144.398px; left: 467px; z-index: 1; padding: 0px; height: 16px !important;"></keeper-lock></div>
        <div class="form-group">
            <input type="password" name=password id=password class="form-control" placeholder="Password" required="required" data-keeper-lock-id="k-tyvemnw2449">
        <keeper-lock class="focus-visible keeper-lock-disabled" tabindex="0" id="k-tyvemnw2449" aria-label="Open Keeper Popup" role="button" style="background-image: url(&quot;chrome-extension://bfogiafebfohielmmehodmfbbebbbpei/images/ico-field-fill-lock-grey.svg&quot;) !important; background-size: 16px 16px !important; cursor: pointer !important; width: 16px !important; position: absolute !important; opacity: 0 !important; margin-top: auto !important; min-width: 16px !important; top: 198.398px; left: 467px; z-index: 1; padding: 0px; height: 16px !important;"></keeper-lock></div>
        <div class="form-group">
            <button type="submit" class="btn btn-primary btn-block">Log in</button>
        </div>
        <div class="clearfix">
            <label class="float-left form-check-label"><input type="checkbox"> Remember me</label>
            <a href="#" class="float-right">Forgot Password?</a>
        </div>        
    </form>
</div>