Получение 404 для запроса CORS к веб-API только в Chrome и только на сервере

Я пытаюсь отправить данные POST с веб-сайта в конечную точку веб-API на том же сервере с тем же доменным именем, но с другим номером порта. Он работает с IE11 как локально, так и на нашем тестовом сервере, но Chrome работает только локально. На тестовом сервере получаю ошибку 404. Насколько я могу судить, он квалифицируется как «простой» запрос, однако ошибка 404 показывает, что HTTP-метод был «ОПЦИИ», поэтому он должен выполнять предварительный запрос и не выполнять его.

zone.js:2933 OPTIONS http://example.com:8001/api/search/quickSearch?v=1.35.2664 404 (Not Found)
scheduleTask @ zone.js:2933
webpackJsonp.../../../../zone.js/dist/zone.js.ZoneDelegate.scheduleTask @ zone.js:411
onScheduleTask @ zone.js:301
webpackJsonp.../../../../zone.js/dist/zone.js.ZoneDelegate.scheduleTask @ zone.js:405
webpackJsonp.../../../../zone.js/dist/zone.js.Zone.scheduleTask @ zone.js:236
webpackJsonp.../../../../zone.js/dist/zone.js.Zone.scheduleMacroTask @ zone.js:259
(anonymous) @ zone.js:2966
proto.(anonymous function) @ zone.js:1366
(anonymous) @ angular.js:12587
sendReq @ angular.js:12332
serverRequest @ angular.js:12084
processQueue @ angular.js:16832
(anonymous) @ angular.js:16876
$digest @ angular.js:17971
(anonymous) @ static.js:1502
schedulerFn @ core.js:4351
webpackJsonp.../../../../rxjs/_esm5/Subscriber.js.SafeSubscriber.__tryOrUnsub @ Subscriber.js:240
webpackJsonp.../../../../rxjs/_esm5/Subscriber.js.SafeSubscriber.next @ Subscriber.js:187
webpackJsonp.../../../../rxjs/_esm5/Subscriber.js.Subscriber._next @ Subscriber.js:128
webpackJsonp.../../../../rxjs/_esm5/Subscriber.js.Subscriber.next @ Subscriber.js:92
webpackJsonp.../../../../rxjs/_esm5/Subject.js.Subject.next @ Subject.js:56
webpackJsonp.../../../core/esm5/core.js.EventEmitter.emit @ core.js:4319
checkStable @ core.js:4718
onLeave @ core.js:4797
onInvokeTask @ core.js:4747
webpackJsonp.../../../../zone.js/dist/zone.js.ZoneDelegate.invokeTask @ zone.js:424
webpackJsonp.../../../../zone.js/dist/zone.js.Zone.runTask @ zone.js:192
webpackJsonp.../../../../zone.js/dist/zone.js.ZoneTask.invokeTask @ zone.js:499
ZoneTask.invoke @ zone.js:488
timer @ zone.js:2040
setTimeout (async)
scheduleTask @ zone.js:2056
webpackJsonp.../../../../zone.js/dist/zone.js.ZoneDelegate.scheduleTask @ zone.js:411
onScheduleTask @ zone.js:301
webpackJsonp.../../../../zone.js/dist/zone.js.ZoneDelegate.scheduleTask @ zone.js:405
webpackJsonp.../../../../zone.js/dist/zone.js.Zone.scheduleTask @ zone.js:236
webpackJsonp.../../../../zone.js/dist/zone.js.Zone.scheduleMacroTask @ zone.js:259
(anonymous) @ zone.js:2072
proto.(anonymous function) @ zone.js:1366
setTimeout @ lodash.js:6663
timerExpired @ lodash.js:10388
webpackJsonp.../../../../zone.js/dist/zone.js.ZoneDelegate.invokeTask @ zone.js:425
onInvokeTask @ core.js:4744
webpackJsonp.../../../../zone.js/dist/zone.js.ZoneDelegate.invokeTask @ zone.js:424
webpackJsonp.../../../../zone.js/dist/zone.js.Zone.runTask @ zone.js:192
webpackJsonp.../../../../zone.js/dist/zone.js.ZoneTask.invokeTask @ zone.js:499
ZoneTask.invoke @ zone.js:488
timer @ zone.js:2040
setTimeout (async)
scheduleTask @ zone.js:2056
webpackJsonp.../../../../zone.js/dist/zone.js.ZoneDelegate.scheduleTask @ zone.js:411
onScheduleTask @ zone.js:301
webpackJsonp.../../../../zone.js/dist/zone.js.ZoneDelegate.scheduleTask @ zone.js:405
webpackJsonp.../../../../zone.js/dist/zone.js.Zone.scheduleTask @ zone.js:236
webpackJsonp.../../../../zone.js/dist/zone.js.Zone.scheduleMacroTask @ zone.js:259
(anonymous) @ zone.js:2072
proto.(anonymous function) @ zone.js:1366
setTimeout @ lodash.js:6663
leadingEdge @ lodash.js:10358
debounced @ lodash.js:10425
fn @ VM445:4
$eval @ angular.js:18161
(anonymous) @ angular.js:25998
(anonymous) @ angular.js:28813
forEach @ angular.js:403
$$writeModelToScope @ angular.js:28811
writeToModelIfNeeded @ angular.js:28804
(anonymous) @ angular.js:28798
validationDone @ angular.js:28723
processAsyncValidators @ angular.js:28706
$$runValidators @ angular.js:28650
$$parseAndValidate @ angular.js:28791
$commitViewValue @ angular.js:28757
(anonymous) @ angular.js:28898
$eval @ angular.js:18161
$apply @ angular.js:18261
$$debounceViewValueCommit @ angular.js:28897
$setViewValue @ angular.js:28875
listener @ angular.js:24822
dispatch @ jquery.js:4737
elemData.handle @ jquery.js:4549
webpackJsonp.../../../../zone.js/dist/zone.js.ZoneDelegate.invokeTask @ zone.js:425
onInvokeTask @ core.js:4744
webpackJsonp.../../../../zone.js/dist/zone.js.ZoneDelegate.invokeTask @ zone.js:424
webpackJsonp.../../../../zone.js/dist/zone.js.Zone.runTask @ zone.js:192
webpackJsonp.../../../../zone.js/dist/zone.js.ZoneTask.invokeTask @ zone.js:499
invokeTask @ zone.js:1540
globalZoneAwareCallback @ zone.js:1566
(index):1 Failed to load http://example.com:8001/api/search/quickSearch?v=1.35.2664: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://example.com' is therefore not allowed access. The response had HTTP status code 404.

Вот как выглядит мой Global.asax для включения запросов CORS:

    protected void Application_BeginRequest(object sender, EventArgs e)
    {
        HttpContext.Current.Response.AddHeader("Access-Control-Allow-Origin", ConfigurationManager.AppSettings["RootUri"].TrimEnd('/'));
        HttpContext.Current.Response.AddHeader("Access-Control-Allow-Methods", "GET, POST, HEAD, PUT, DELETE, OPTIONS");
        HttpContext.Current.Response.AddHeader("Access-Control-Max-Age", "30");
        HttpContext.Current.Response.AddHeader("Access-Control-Allow-Credentials", "true");
        HttpContext.Current.Response.AddHeader("Access-Control-Allow-Headers", "Accept, Accept-CH, Accept-Charset, Accept-Datetime, Accept-Encoding, Accept-Ext, Accept-Features, Accept-Language, Accept-Params, Accept-Ranges, Access-Control-Allow-Credentials, Access-Control-Allow-Headers, Access-Control-Allow-Methods, Access-Control-Allow-Origin, Access-Control-Expose-Headers, Access-Control-Max-Age, Access-Control-Request-Headers, Access-Control-Request-Method, Age, Allow, Alternates, Authentication-Info, Authorization, C-Ext, C-Man, C-Opt, C-PEP, C-PEP-Info, CONNECT, Cache-Control, Compliance, Connection, Content-Base, Content-Disposition, Content-Encoding, Content-ID, Content-Language, Content-Length, Content-Location, Content-MD5, Content-Range, Content-Script-Type, Content-Security-Policy, Content-Style-Type, Content-Transfer-Encoding, Content-Type, Content-Version, Cookie, Cost, DAV, DELETE, DNT, DPR, Date, Default-Style, Delta-Base, Depth, Derived-From, Destination, Differential-ID, Digest, ETag, Expect, Expires, Ext, From, GET, GetProfile, HEAD, HTTP-date, Host, IM, If, If-Match, If-Modified-Since, If-None-Match, If-Range, If-Unmodified-Since, Keep-Alive, Label, Last-Event-ID, Last-Modified, Link, Location, Lock-Token, MIME-Version, Man, Max-Forwards, Media-Range, Message-ID, Meter, Negotiate, Non-Compliance, OPTION, OPTIONS, OWS, Opt, Optional, Ordering-Type, Origin, Overwrite, P3P, PEP, PICS-Label, POST, PUT, Pep-Info, Permanent, Position, Pragma, ProfileObject, Protocol, Protocol-Query, Protocol-Request, Proxy-Authenticate, Proxy-Authentication-Info, Proxy-Authorization, Proxy-Features, Proxy-Instruction, Public, RWS, Range, Referer, Refresh, Resolution-Hint, Resolver-Location, Retry-After, Safe, Sec-Websocket-Extensions, Sec-Websocket-Key, Sec-Websocket-Origin, Sec-Websocket-Protocol, Sec-Websocket-Version, Security-Scheme, Server, Set-Cookie, Set-Cookie2, SetProfile, SoapAction, Status, Status-URI, Strict-Transport-Security, SubOK, Subst, Surrogate-Capability, Surrogate-Control, TCN, TE, TRACE, Timeout, Title, Trailer, Transfer-Encoding, UA-Color, UA-Media, UA-Pixels, UA-Resolution, UA-Windowpixels, URI, Upgrade, User-Agent, Variant-Vary, Vary, Version, Via, Viewport-Width, WWW-Authenticate, Want-Digest, Warning, Width, X-Content-Duration, X-Content-Security-Policy, X-Content-Type-Options, X-CustomHeader, X-DNSPrefetch-Control, X-Forwarded-For, X-Forwarded-Port, X-Forwarded-Proto, X-Frame-Options, X-Modified, X-OTHER, X-PING, X-PINGOTHER, X-Powered-By, X-Requested-With");

        // If a preflight request, end it so we don't fetch data.
        if (HttpContext.Current.Request.HttpMethod == "OPTIONS")
        {
            HttpContext.Current.Response.End();
        }
    }

Почему я получаю 404 и как это исправить?