Creation of two select box under a form - html

Question

I am trying to create two drop-down select box in my page..But something happening wrong ..when I run the code, the button bellow and the footer section get vanished.I tried by making height larger but nothing ...again when i remove the select box's code the page load properly with the register button and footer section...For more clearance an image is given bellow.The whole code is under a form..and the form is under a div name maincontent..I have given the css of the maincontent
here is my code
`.maincontent {
margin-top: 200px;
background: #E0E0E0;
float: left;
border: 1px solid #013A57;
padding: 3px 2px;
margin-top: 0px;
border-radius: 5px;
height: 750pxmain;
width: 900px;
margin-left: 15px;
height: 750px;
}
.maincontent table{
height: 20%;
overflow-y: scroll;
width: 55%;
margin-top: 30px;
margin-left: 30px
}
.maincontent tr{
background: #E0E0E0;
border-bottom: 1px solid #FFF;
margin-bottom: 5px;
}
.maincontent td{
font-family: 'Lato', sans-serif;
font-weight: bold;
padding: 10px;
text-align: left;
width: 33.3333%;
font-size: 12px;
}
.maincontent h3{
padding: 10px;
border-bottom: 2px solid #013A57;
margin: 10px;
font-size: 23px;
color: #013A57;
}`
<div class="maincontent" style="">
<h3>Register Here</h3>
<div class="row justify-content-center" style="float: left;margin-left:
2px;margin-top: 50px">
<div class="col" style="width: 200px">
<?php if(!empty($msg)) { ?>
div id="dialog" title="" style="background: #013A57; color: white;">
<?php echo $msg;?>
</div>
<?php }?>
<form method="post" action="register.php" enctype="multipart/form- data"
style="width: 860px;margin: 0px;height: 580px;">
<input class="form-control" type="" name="name" placeholder="Name..."
style="width: 400px; margin-left: 200px" ><br>
<input class="form-control" type="email" name="email"
placeholder="Email..." style="width: 400px; margin-left: 200px" ><br>
<input class="form-control" type="password" name="password"
placeholder="Password" style="width: 400px; margin-left: 200px" ><br>
<input class="form-control" type="password" name="cPassword"
placeholder="confirm Password..." style="width: 400px; margin-left: 200px"
><br>
<input class="form-control" type="text" name="contactNO" placeholder="Your
contact No.." style="width: 400px; margin-left: 200px" ><br>
<div class="radio">
<h6>Select a Category</h6>
<input type="radio" name="category" value="customer">Customer<br>
<input type="radio" name="category" value="DispensaryOwner">Dispensary
Owner<br>
<input type="radio" name="category" value="dealer">Dealer<br>
</div>
<br>
<div class="address radio" >
<h6 style="margin-left: 20px">Address</h6>
<select name="district" id="district">
<option value="">Select District</option>
<?php echo load_district(); ?>
</select>
<br>
<select name="place" id="place">
<option value="">Select place</option>
</select>
</div>
<br>
<input class="btn-primary" type="submit" name="submit" value="Register"
style=" margin-left: 200px"><br><br>
</form>
</div>
</div>
</div>
Image Before
Image After