Error when using jQuery Ajax POST (json) with php - php

Question

On page load I use this code to display data from database:
<script>
$(function feed(){
var page = 1;
var type = '<?php echo $filter ;?>';
var theData = {};
theData['page'] = 'profile';
theData['type'] = type;
theData['username'] = '<?php echo $user_data->username; ?>';
theData['get_activities'] = 'true';
$.ajax({
type: "POST",
url: "data.php",
data: theData,
dataType:'json',
success: function(data){
$("#activities").html(data.activity_feed);
if(page < data.total_pages){
$("#activities").after('<div id="loader"><button id="load_more_activities">Load more</button></div>');
}
}
});
$("#activity_container").on("click", "#load_more_activities", function(){
var next = page+=1;
var type = '<?php echo $filter ;?>';
var theData = {};
theData['page'] = 'profile';
theData['type'] = type;
theData['username'] = '<?php echo $user_data->username; ?>';
theData['get_activities'] = 'true';
theData['page_num'] = next;
$.ajax({
type: "POST",
url: "data.php",
data: theData,
dataType: "json",
success: function(data){
$("#activities").append(data.activity_feed);
if(next == data.total_pages){
$("#loader").html("No more data");
} else {
$("#loader").html('<div id="loader"><button id="load_more_activities">Load more</button></div>');
}
},
});
});
});
</script>
Everything work fine, but if I refresh page more than 5 or 6 times or if load_more_activities function is called more than 5 or 6 times...then post is not executed and I don't get any data displayed...
Is something wrong with this code or there are maybe some restrictions from my host provider?
When post is executed:
When post is not executed:

Answer 1

My host provider has a protection from several sending ajax data with variables named "username" or "password". So when this happens, server detect some kind »brute-force« and then drop-all-packets.