是什麼導致XML分析錯誤：找不到根元素錯誤？

Question

我最近開始越來越在Firebug顯示以下錯誤：

XML Parsing Error: no root element found Location: http://dd.example.com/1.0/sources/30 Line Number 1, Column 1: 30:1:1

什麼原因引起的，如何解決？

頭選項卡：

Request URL: http://dd.example.com/1.0/sources/30 
Request Method: PUT 
Remote address: 11.11.111.111:80 
Status Code: 204 No Content 
Version: HTTP/1.1 

請求報頭：

Host: dd.example.com 
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:51.0) Gecko/20100101 Firefox/51.0 
Accept: */* 
Accept-Language: en-US,en;q=0.5 
Accept-Encoding: gzip, deflate 
Referer: http://dd.example.com/ 
Content-Type: application/x-www-form-urlencoded; charset=UTF-8 
X-Requested-With: XMLHttpRequest 
Content-Length: 33 
Cookie: _ga=GA1.2.1885184115.1475238275; PHPSESSID=7ggri150scu2g5et1f7gtone94 
Authorization: Basic TEljaGGlcDqTdW5zaKfrZX== 
Connection: keep-alive 

請求正文：

name=name&value=Remote+Sock&pk=30 

響應頭：

Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0 
Connection: close 
Content-Length: 0 
Content-Type: 
Date: Sun, 05 Feb 2017 16:59:50 GMT 
Expires: Thu, 19 Nov 1981 08:52:00 GMT 
Pragma: no-cache 
Server: Apache/2.2.15 (CentOS) 
X-Powered-By: PHP/5. 

Answer 1

正在發送狀態碼204但尚未嘗試發送內容。