Предварительная проверка OPTIONS дает 403 с Access-Control-Allow-Origin "*"

У меня есть одностраничное приложение, обслуживаемое на одном поддомене, а api - на другом. Я получаю 403 Forbidden на предполетной проверке для отправки XHR POST в api.

Отладка в curl показывает:

 curl  -H "Host: backend-sjm-staging.a3c1.starter-us-west-1.openshiftapps.com" \
 -H "Origin: http://frontend-sjm-staging.a3c1.starter-us-west-1.openshiftapps.com" \
-H "Access-Control-Request-Method: POST" \
-H "Access-Control-Request-Headers: content-type" \
-X OPTIONS --verbose http://backend-sjm-staging.a3c1.starter-us-west-1.openshiftapps.com/api/users
*   Trying 54.153.79.158...
* TCP_NODELAY set
* Connected to backend-sjm-staging.a3c1.starter-us-west-1.openshiftapps.com (54.153.79.158) port 80 (#0)
> OPTIONS /api/users HTTP/1.1
> Host: backend-sjm-staging.a3c1.starter-us-west-1.openshiftapps.com
> User-Agent: curl/7.54.0
> Accept: */*
> Origin: http://frontend-sjm-staging.a3c1.starter-us-west-1.openshiftapps.com
> Access-Control-Request-Method: POST
> Access-Control-Request-Headers: content-type
> 
* HTTP 1.0, assume close after body
< HTTP/1.0 403 Forbidden
< Date: Fri, 04 May 2018 21:16:52 GMT
< Server: Apache/2.4.27 (Red Hat) OpenSSL/1.0.1e-fips
< Cache-Control: no-cache, private
< Access-Control-Allow-Origin: *
< Access-Control-Allow-Headers: accept, access-control-allow-origin, content-type
< Access-Control-Allow-Methods: PUT, GET, POST, DELETE, OPTIONS
< Content-Length: 18
< Content-Type: text/html; charset=UTF-8
< Set-Cookie: 45fe47f0bb613513b8e98d0599b628f9=dd4b5c95b51d6168419458748b392421; path=/; HttpOnly
* HTTP/1.0 connection set to keep alive!
< Connection: keep-alive
< 
* Connection #0 to host backend-sjm-staging.a3c1.starter-us-west-1.openshiftapps.com left intact
Origin not allowed

Тем не менее, Access-Control-Allow-Origin: * в ответе предполагает, что он должен разрешить Origin: http://frontend-sjm-staging.a3c1.starter-us-west-1.openshiftapps.com названный запрос.

Если я отброшу заголовок Origin из запроса, я получу 200.

Я попытался явно настроить Access-Control-Allow-Origin на сервере, чтобы он соответствовал Origin запроса, но он также возвращает 403:

 curl  -H "Host: backend-sjm-staging.a3c1.starter-us-west-1.openshiftapps.com" \
 -H "Origin: http://frontend-sjm-staging.a3c1.starter-us-west-1.openshiftapps.com" \
-H "Access-Control-Request-Method: POST" \
-H "Access-Control-Request-Headers: content-type" \
-X OPTIONS --verbose http://backend-sjm-staging.a3c1.starter-us-west-1.openshiftapps.com/api/users
*   Trying 54.153.79.158...
* TCP_NODELAY set
* Connected to backend-sjm-staging.a3c1.starter-us-west-1.openshiftapps.com (54.153.79.158) port 80 (#0)
> OPTIONS /api/users HTTP/1.1
> Host: backend-sjm-staging.a3c1.starter-us-west-1.openshiftapps.com
> User-Agent: curl/7.54.0
> Accept: */*
> Origin: http://frontend-sjm-staging.a3c1.starter-us-west-1.openshiftapps.com
> Access-Control-Request-Method: POST
> Access-Control-Request-Headers: content-type
> 
* HTTP 1.0, assume close after body
< HTTP/1.0 403 Forbidden
< Date: Fri, 04 May 2018 21:32:52 GMT
< Server: Apache/2.4.27 (Red Hat) OpenSSL/1.0.1e-fips
< Cache-Control: no-cache, private
< Access-Control-Allow-Origin: http://frontend-sjm-staging.a3c1.starter-us-west-1.openshiftapps.com
< Access-Control-Allow-Headers: accept, access-control-allow-origin, content-type
< Access-Control-Allow-Methods: PUT, GET, POST, DELETE, OPTIONS
< Content-Length: 18
< Content-Type: text/html; charset=UTF-8
< Set-Cookie: 45fe47f0bb613513b8e98d0599b628f9=a913ecc9ded73c3ac76fbb38d93e15a7; path=/; HttpOnly
* HTTP/1.0 connection set to keep alive!
< Connection: keep-alive
< 
* Connection #0 to host backend-sjm-staging.a3c1.starter-us-west-1.openshiftapps.com left intact
Origin not allowed

На сервере .htaccess имеет следующую конфигурацию:

<IfModule mod_headers.c>
    Header add Access-Control-Allow-Origin "http://frontend-sjm-staging.a3c1.starter-us-west-1.openshiftapps.com"
    Header add Access-Control-Allow-Headers "accept, access-control-allow-origin, content-type"
    Header add Access-Control-Allow-Methods "PUT, GET, POST, DELETE, OPTIONS"
</IfModule>

Установка Access-Control-Allow-Origin на "*" не решает проблему.

Почему ответ 403 запрещен, если источник кажется разрешенным, и как это исправить?

Спасибо!

ОБНОВИТЬ

Вот мой последний .htaccess, предназначенный для PHP-бэкэнда laravel:

<IfModule mod_rewrite.c>
    <IfModule mod_negotiation.c>
        Options -MultiViews -Indexes
    </IfModule>

    RewriteEngine On

    # Handle Authorization Header
    RewriteCond %{HTTP:Authorization} .
    RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]

    # Redirect Trailing Slashes If Not A Folder...
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteCond %{REQUEST_URI} (.+)/$
    RewriteRule ^ %1 [L,R=301]

    # Handle Front Controller...
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteRule ^ index.php [L]
</IfModule>
<IfModule mod_headers.c>
    Header add Access-Control-Allow-Origin "*"
    Header add Access-Control-Allow-Headers "*"
    Header add Access-Control-Allow-Methods "PUT, GET, POST, DELETE, OPTIONS"
</IfModule>