my website shows 500 internal server error , when receiving ajax response - php

Question

It shows 500 internal server error when retrieving data through ajax. But the whole code works well in my localhost. And i am facing this error for the first time, so i am not sure whether this error is caused due to fetching data through AJAX. If it is not the correct reason please get me the correct reason.
this is my coding
$.ajax({
type:"POST",
url:"api_fle/get_post",
data:{u_id:u_id,type:'all13'},
success:function(response){
if(response!=0){
var parsed = $.parseJSON(response);
date = new Array();
events = new Array();
$.each(parsed,function(i,parsed){
if(parsed.shred.length>15){var shred=jQuery.trim(parsed.shred).substring(0, 14) + '...';} else{var shred=parsed.shred;}
if(parsed.cmpny_name == parsed.shred){var sharedd=parsed.cmpny_name; var sha=""; var pic=parsed.pro_pic;}else{var sharedd=shred; var sha=' shared <input type="hidden" id="who_hid_id" value="'+parsed.id+'">'+parsed.cmpny_name+"'s Event"; var pic=parsed.pic;}
date[i]=parsed.SharedDate;
events[i]='<div class="col-md-10 post" style="background:#FFF"><span class="company-logo-small"><img src="'+pic+'" style=" width: 60px; height: 60px;"></span>'
+'<span class="fullhead"><span class="posted-name"><a id="who_shred" style="color:#fff;cursor:pointer;"><input type="hidden" id="who_hid_id" value="'+parsed.id+'"><span itemprop="hiringOrganization">'+sharedd+'</span></a>'+sha+'</span></span>'
+'<span class="post-status" style="color:#fff;">'+prettyDate(parsed.SharedDate)+'</span><div class="post-inner"><div class="col-md-12"><div class="panel panel-default event">'
+'<div class="panel-heading title">'+parsed.name+'</div><ul class="list-group"><li class="list-group-item"><i class="fa fa-globe"></i>'+parsed.location+'</li>'
+'<li class="list-group-item"><i class="fa fa-calendar-o"></i>'+parsed.date+'</li><li class="list-group-item"><i class="fa fa-clock-o"></i>'+parsed.time+'</li>'
+'<li class="list-group-item"><i class="fa fa-users"></i>Attendees '+parsed.attendies+'</li></ul><ul class="list-group"><div class="panel-body"><p>'+parsed.decs+'</p>'
+'<a class="btn btn-xs btn-info pull-left" target="_blank" href="eventview?evnt_id='+parsed.evnt_id+'">View</a>&nbsp&nbsp'
+'<i class="fa fa-fw fa-facebook-square" style="font-size:20px;"></i>'
+'<a class="twitter popup" href="pagelink?evnt_id='+parsed.evnt_id+'" target="_blank"><i class="fa fa-fw fa-twitter-square " style="font-size:20px;"></i></a>'
+'<a class="twitter popup" href="pagelink?evnt_id='+parsed.evnt_id+'" target="_blank">'
+'<i class="fa fa-fw fa-linkedin-square" style="font-size:20px;"></i></a><a class="twitter popup" href="pagelink?evnt_id='+parsed.evnt_id+'" target="_blank">'
+'<i class="fa fa-fw fa-google-plus" style="font-size:20px;"></i></a></div></ul><div id="img"></div><div class="clearfix"></div></div></div></div></div>';
});
}
});
-------------------------
page : get_post
--------------------
if($_POST['type']=='all13'){
$update_time=mysql_query("UPDATE `share_post` SET `sharedDate`='".$_POST['time']."' WHERE `frm_id` = 'U005114608238'");
$sql=select_query("SELECT s.id,e.u_id,e.cmpny_name,n.pro_pic as pic,l.pro_pic,l.level as lv,m.evnt_id,m.name,m.location,m.decs,m.time,
m.date,m.attendies,s.frm_id,s.is_important,s.shred,s.SharedDate,s.lvl FROM employer_info e,login l,login n,`event` m, share_post s WHERE n.u_id=s.frm_id and e.u_id=l.u_id and m.u_id=l.u_id and m.evnt_id=s.post_id and s.to_id='".$_POST['u_id']."' order by s.id desc");
$count=count($sql);
$response=array();
for($i=0;$i<$count;$i++){
array_push($response,$sql[$i]);
}
echo json_encode($response);
}
when i have inspected the error , i got something like in this screenshot