Apache mod_proxy ssl to non ssl, login not working

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Hello Together,
I have a problem to login, if i used mod_proxy from a non ssl site to roundcube on ssl.
I have installed roundcube on a subdomain with SSL:
​https://webmail.ssldomain.com/
this work, no problems if user take this domain. But I want the same on other Domains without a SSL Certificate, so I use mod_proxy:

Code Select Expand

<VirtualHost *:80>
    ServerName webmail.DomainWithoutSSL.com
    ServerAdmin [email protected]
    ServerAlias webmail.DomainWithoutSSL.com

    SSLProxyEngine On
    ProxyPass / https://webmail.SSLDomain.com/
    ProxyPassReverse / https://webmail.SSLDomain.com/
    ProxyPassReverseCookieDomain webmail.SSLDomain.com webmail.DomainWithoutSSL.com
#   ProxyPassReverseCookiePath / /
    RedirectMatch ^/$ http://webmail.DomainWithoutSSL.com

    ProxyRequests Off
    <Proxy *>
        Order deny,allow
        Allow from all
    </Proxy>
</VirtualHost>
But if a user want to login, the error REQUEST_ERROR_TOKEN will promt. Because $token is every time unequal $sess_tok in rcube.php line 1082. I can't found out why! Can you help me?
Thank you