.htaccess redirect https to http not working

Question

I am trying to catch any https traffic to the front of my site so:

https://www.domain.com

is redirected to:

http://www.domain.com

However other subdomains need to be redirected elsewhere. For the most part this is all working, apart from the https -> http redirection. Here's my .htaccess file at the moment:

RewriteEngine On

RewriteCond %{HTTPS} on
RewriteRule (.*) http://%{HTTP_HOST}%{REQUEST_URI}

RewriteCond %{HTTP_HOST} ^domain\.com [NC]
RewriteRule ^(.*)$ http://www.domain.com/$1 [L,R=301]

RewriteCond "%{HTTP_HOST}" !^www.* [NC]
RewriteCond "%{HTTP_HOST}" ^([^\.]+).*$
RewriteRule ^(.*)$ https://secure.domain.com/a/login/%1 [L,R=301]

It would seem that this bit:

RewriteCond %{HTTPS} on
RewriteRule (.*) http://%{HTTP_HOST}%{REQUEST_URI}

isn't working as I would imagine. In fact it doesn't seem to redirect at all.

In another subdirectory I have the opposite in effect which works fine:

RewriteCond %{HTTPS} off
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI}

so my thinking is the opposite should have done the job, but seemingly not.

Any thoughts anyone?

EDIT

I'm thinking that this could have something to do with the fact that on the server there is an ssl cert which the ISP uses to provide a generic https address to your site. For example if you have a site at:

http://www.yourdomain.com

You can access the same content/hosting account over https by using:

https://server100.securedomain.com/yourdomain.com

Could it be that because when I type in https into the browser I'm being served the generic cert and because it doesn't match the domain name I've entered I'm getting a security warning about an untrusted cert which is stopping the redirection?

EDIT 2

Looking at the server headers I think I am correct with my above assumption. The server is returning:

The host name in the certificate is invalid or does not match

Would this stop the redirection?

Answer 1

If "it doesn't seem to redirect at all" my guess is that

RewriteCond %{HTTPS} on

fails for some reason. I saw this in an example:

RewriteCond %{SERVER_PORT} ^443$ [OR]
RewriteCond %{HTTPS} =on

Maybe you need both?