I work on an Android project, in which I use AsyncTask to send nameValuePairs to webservice.
I use PHP code below to send data from application to database:
<?php
  require_once('dbConnect.php');
  $studentid = $_POST['name'];
  $classid = $_POST['classid']
  $studentid = $_POST['studentid'];
  $start = $_POST['start'];
  $end = $_POST['end'];
  $startsig = $_POST['startsig'];
  $endsig = $_POST['endsig'];
  $sql = "insert into signature (studentid,classid,start,end,startsig,endsig) values ('$studentid','$classid','$start','$end','$startsig','$endsig')";
  if(mysqli_query($con,$sql)){
    echo 'success';
  }
  else{
    echo 'failure';
  }
  mysqli_close($con);
?>
Values in dbConnect.php file are correct. Database schema looks like this.

I checked, application sends out data successfully, but when I try to access PHP file above from browser I get a HTTP 500 error.
What else should I check in this case?
 
    