on click triggering of fb share dialog box not working - facebook

Question

I have one online treasure hunt website.When a user enter a correct answer it will show a page which has a continue button. When we click that continue button a facebook share dialog box will appear. The onclick function for that button is as follows.
<div class="row" >
<div class="text-center">
<?php if($result==TRUE): ?>
<a onclick="FB.ui({
method: 'share',
href: '',
quote: 'Successfully Completed Level <?php echo $level-1 ?> . An Exciting Online Treasure Hunt',
hashtag: '',
}, function(response){
location.href ='<?php echo base_url() ?>';
});" class="buttonfb btn btn-lg btn-success" role="button">Continue</a>
<?php else: ?>
Try Again
<?php endif; ?>
</div></div></div>
Here it will trigger a fb share dialog box which makes it able for user to share his achievement on fb. But the error is that when the dialog box for share appears an error message is written in dialog box. It is as follows
Can't load URL: The domain of this URL isn't included in the app's
domains. To be able to load this URL, add all domains and sub-domains
of your app to the App Domains field in your app settings.
This is my script
<script>
window.fbAsyncInit = function() {
FB.init({
appId : 'here i set my app id',
xfbml : true,
version : 'v2.8'
});
FB.AppEvents.logPageView();
};
(function(d, s, id){
var js, fjs = d.getElementsByTagName(s)[0];
if (d.getElementById(id)) {return;}
js = d.createElement(s); js.id = id;
js.src = "//connect.facebook.net/en_US/sdk.js";
fjs.parentNode.insertBefore(js, fjs);
}(document, 'script', 'facebook-jssdk'));
</script>
I already have added app domains and URL correctly in my Facebook app. Also, I have a login with Facebook button in my home page. The login with Facebook button is working fine, but the share dialog box shows this error.
Please help me.