AJAX请求返回错误

Question

I have an AJAX request that is throwing an error.

It's part of a larger system that I've inherited, so I can't post the files in their entirety, but I've tried to isolate the relevant code:

$.ajax(
    {
        url: ajax_url, // Valid URL
        data: jsonData, // Valid JSON
        dataType: 'json',
        contentType: 'application/json',
        type: POST, 
        async:true, 
        success: function(data) 
        {
            console.log(data);
            parsedData = JSON.parse(data);
            console.log(parsedData);
            // Here I am trying to log successful output
        },
        error: function(jsonData) 
        {
            console.log("error");
            console.log(jsonData);
        }
    });

In the PHP, values are added to an array and returned:

$data['status']=200;
$data['new_id']=$insert_id;
return json_encode($data);

All I am logging at the moment is 'error'. Apologies again for incomplete code, I have tried to supply the code where I think the error is caused.