Need help: getting a Bootstrap email contact form to work from HTML/PHP code -

i setting blog , have contact form page (standard bootstrap blog template)

i have uploaded onto host - hostgator, can't manage contact form send email out properly.

i have tried both external email account , account on same domain name no luck.

here original html source contact page bootstrap: https://github.com/ironsummitmedia/startbootstrap-clean-blog/blob/gh-pages/contact.html

and original source contact_me.php: https://github.com/ironsummitmedia/startbootstrap-clean-blog/blob/gh-pages/mail/contact_me.php

is there setting need change hostgator cpanel or in code i'm missing?

edit: here domain if want view source have in place: www.decentralizeblog.com

i have made bit changes form
have not used attributes in form

link method, action , name attribute in text field

            <form name="sentmessage" id="contactform" action="mailer.php" method="post" novalidate>                 <div class="row control-group">                     <div class="form-group col-xs-12 floating-label-form-group controls">                         <label>name</label>                         <input type="text" name="name" class="form-control" placeholder="name" id="name" required data-validation-required-message="please enter name.">                         <p class="help-block text-danger"></p>                     </div>                 </div>                 <div class="row control-group">                     <div class="form-group col-xs-12 floating-label-form-group controls">                         <label>email address</label>                         <input type="email" name="email" class="form-control" placeholder="email address" id="email" required data-validation-required-message="please enter email address.">                         <p class="help-block text-danger"></p>                     </div>                 </div>                 <div class="row control-group">                     <div class="form-group col-xs-12 floating-label-form-group controls">                         <label>phone number</label>                         <input type="tel" name="phone" class="form-control" placeholder="phone number" id="phone" required data-validation-required-message="please enter phone number.">                         <p class="help-block text-danger"></p>                     </div>                 </div>                 <div class="row control-group">                     <div class="form-group col-xs-12 floating-label-form-group controls">                         <label>message</label>                         <textarea rows="5" name="message" class="form-control" placeholder="message" id="message" required data-validation-required-message="please enter message."></textarea>                         <p class="help-block text-danger"></p>                     </div>                 </div>                 <br>                 <div id="success"></div>                 <div class="row">                     <div class="form-group col-xs-12">                         <button type="submit" class="btn btn-default">send</button>                     </div>                 </div>             </form>