Topic on Help talk:Logging in

I can't change the password. It always says, that the channel is not secure to transfer the new password. But I have a SSL connection to the website.

Are you using this form? Special:ChangePassword

I mean on my website. Here I haven't tried.

Maybe MediaWiki doesn't recognize the page as being served by https.

If your website is served by a reverse proxy and behind an internal network, be sure to pass the protocol being forwarded. On nginx you usually add a X-Forwarded-Proto request header with:

proxy_set_header X-Forwarded-Proto $scheme