Chrome和Firefox CORS AJAX呼叫在某些Mac机器上被中止

我们在www.saddleBACk.com/live上有一个网页，Chrome和Firefox CORS AJAX调用在某些Mac机器上被中止。在装有OSX
10.9（最新更新），Chrome和Firefox（最新更新）的Mac上，对http://api.saddleBACk.com/Worshipservice?version=2&null&_=1386201207191的AJAX调用被终止。这适用于Safari。

此行为是孤立的，但在某些计算机上可重现，但在其他计算机上则无法重现。我们还有其他具有相同操作系统和浏览器版本的Mac机器，它们可以成功打开该网页。

我已验证Web服务器在500毫秒内成功响应了AJAX请求。但是Chrome会等待约30秒，等待响应，并最终终止通话。我为以下失败的电话添加了chrome：//
net-internals：

11645: URL_requEST
http://api.saddleBACk.com/Worshipservice?version=2&null&_=1386201207191
Start Time: 2013-12-04 15:53:27.469

t=1386201207469 [st=    0] +requEST_ALIVE  [dt=30398]
t=1386201207470 [st=    1]   +URL_requEST_START_JOB  [dt=30397]
                              --> load_flags = 143540480 (DO_NOT_SAVE_COOKIES | DO_NOT_SEND_AUTH_DATA | DO_NOT_SEND_COOKIES | ENABLE_LOAD_TIMING | MAYBE_user_GEstuRE | REPORT_RAW_HEADERS | VERIFY_EV_CERT)
                              --> method = "GET"
                              --> priority = 2
                              --> url = "http://api.saddleBACk.com/Worshipservice?version=2&null&_=1386201207191"
t=1386201207470 [st=    1]      http_CACHE_GET_BACKEND  [dt=0]
t=1386201207470 [st=    1]      http_CACHE_OPEN_ENTRY  [dt=0]
                                --> net_error = -2 (ERR_FAILED)
t=1386201207470 [st=    1]      http_CACHE_CREATE_ENTRY  [dt=0]
t=1386201207470 [st=    1]      http_CACHE_ADD_TO_ENTRY  [dt=0]
t=1386201207470 [st=    1]     +http_STREAM_requEST  [dt=2]
t=1386201207472 [st=    3]        http_STREAM_requEST_BOUND_TO_JOB
                                  --> source_dependency = 11647 (http_STREAM_JOB)
t=1386201207472 [st=    3]     -http_STREAM_requEST
t=1386201207472 [st=    3]     +http_transaCTION_SEND_requEST  [dt=0]
t=1386201207472 [st=    3]        http_transaCTION_SEND_requEST_HEADERS
                                  --> GET /Worshipservice?version=2&null&_=1386201207191 http/1.1
                                      Host: api.saddleBACk.com
                                      Connection: keep-alive
                                      Accept: application/json,text/javascript,*/*; q=0.01
                                      Origin: http://www.saddleBACk.com
                                      User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_0) AppleWebKit/537.36 (KHTML,like Gecko) Chrome/31.0.1650.63 Safari/537.36
                                      Content-Type: application/json
                                      Referer: http://www.saddleBACk.com/onlinecampus/
                                      Accept-Encoding: gzip,deflate,sdch
                                      Accept-Language: en-US,en;q=0.8
t=1386201207472 [st=    3]     -http_transaCTION_SEND_requEST
t=1386201207472 [st=    3]     +http_transaCTION_READ_HEADERS  [dt=30395]
t=1386201207472 [st=    3]       +http_STREAM_PARSER_READ_HEADERS  [dt=30395]
t=1386201237867 [st=30398]          CANCELLED
t=1386201237867 [st=30398]   -URL_requEST_START_JOB
                              --> net_error = -3 (ERR_ABORTED)
t=1386201237867 [st=30398] -requEST_ALIVE

这是Wireshark的请求和响应：

请求

GET /Worshipservice?version=2&null&_=1386192341441 http/1.1
    [Expert Info (Chat/SequencE): GET /Worshipservice?version=2&null&_=1386192341441 http/1.1]
        [message: GET /Worshipservice?version=2&null&_=1386192341441 http/1.1]
        [Severity level: Chat]
        [Group: Sequence]
    request Method: GET
    request URI: /Worshipservice?version=2&null&_=1386192341441
    request Version: http/1.1
Host: api.saddleBACk.com
Connection: keep-alive
Cache-Control: max-age=0
Accept: application/json,*/*; q=0.01
Origin: http://www.saddleBACk.com
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_0) AppleWebKit/537.36 (KHTML,like Gecko) Chrome/31.0.1650.57 Safari/537.36
Content-Type: application/json
Referer: http://www.saddleBACk.com/onlinecampus/
Accept-Encoding: gzip,sdch
Accept-Language: en-US,en;q=0.8

响应

http/1.1 200 OK
    [Expert Info (Chat/SequencE): http/1.1 200 OK]
        [message: http/1.1 200 OK]
        [Severity level: Chat]
        [Group: Sequence]
    request Version: http/1.1
    Status Code: 200
    Response Phrase: OK
Cache-Control: no-cache
Pragma: no-cache
Content-Type: application/json; charset=utf-8
Expires: -1
Server: Microsoft-IIS/7.5
Access-Control-Allow-Origin: http://www.saddleBACk.com
Access-Control-Allow-Credentials: true
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
Date: Wed,04 Dec 2013 21:25:41 GMT
Content-Length: 2841
    [Content length: 2841]
Set-Cookie: NSC_ndxfc1-45*80=ffffffffaf181c9545525d5f4f58455e445a4a423660;expires=Wed,04-Dec-2013 14:44:34 GMT;path=/;httponly

我花了太多时间试图弄清楚为什么在某些Mac配置上而不是其他配置上失败。任何帮助将非常感激。