HTTP to HTTPS redirect not working on Apache with PHP

I have a script that handles several different redirects on a server with a snippet that looks like follows:

if($url == "http://www.url.com")
    {header("Location: https://www.url.com/index.html");}

The script works exactly as intended 开发者_运维技巧with one issue - all of the https redirects end up redirecting to http (versus the https as defined).

Does anyone have any ideas what may be going on?

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The server you redirect to has a redirect of its own to http.

Nothing you can do about it, unless you are administering that server.

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There was something else going on with the server, but it's been a while so I can't remember what it was anymore.