Chrome and Firefox CORS AJAX calls get aborted on some Mac machines

We have a webpage at www.saddleback.com/live and Chrome and Firefox CORS AJAX calls get aborted on some Mac machines. On a Mac with OSX 10.9 (latest updates), Chrome and Firefox (with latest updates) the AJAX call to http://api.saddleback.com/WorshipService?version=2&null&_=1386201207191 gets aborted. This works on Safari. This behavior is isolated but reproducible on some machines but not others. We have other Mac machines with identical OS and browser version that successfully bring up the webpage. I have verified that the web server successfully responds to the AJAX request within 500 milliseconds. Yet Chrome hangs on waiting for the response for ~30 seconds and eventually aborts the call. I've included a the chrome://net-internals for the failed call below: ``` 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 ``` Here is the request and response from Wireshark: REQUEST ``` 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, 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/31.0.1650.57 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 ``` RESPONSE ``` 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 ``` I have spent too much time trying to figure out why this is failing on some Mac configuration and not others. Any help would be much appreciated.