Siteground Laravel 500 internal server error ajax randomly

My website is built in laravel 5.4 and hosted on Siteground. The website was working fine before. But now I am randomly getting 500 internal server errors on some ajax request. Sample Code

  var csrf_token = $('meta[name="csrf-token"]').attr('content');
    var postdata = {
        '_token': csrf_token
    };
    $.ajaxSetup({
        headers: {
            'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')
        }
    });

    $.ajax({
        url: url,
        type: 'POST',
        dataType: 'JSON',
        data: postdata,
        success: function(data) {

        },
        error: function(data) {

        }
    });

Kindly help me fix the issue. Thanks in advance.

via Chebli Mohamed