about json is not valid [closed]

if(username !="" && password!=""){
    $.ajax({
        url: 'insert.php',
        type:'post',
        data:{username:username,
            password:password
        },
        dataType: 'json',
        success:function(response){
            alert(response.message);
            $('#form')[0].reset();
        },error:function(xhr,status,error){
            console.error(error);
        }
    });
}else{
    alert("Empty Fields!");
}

when i try to submit it will give me that error on the right side and then online 57 is this console.error(error);