Fixed, it was a CAS issue not a fengoffice problem. We fixed applying this rules in Apache:
RewriteCond context=
RewriteCond %{REQUEST_URI} !^/index.php(.*)$
RewriteRule ^/(.*)$ https://{HTTP_HOST}/index.php$1 [R=301,L]
This rule force the context page from fengoffice go through index.php, before in the CAS redirect was getting a index.html getting an error. Not sure why this redirect to index.html, but with the rule before we force to have a index.php
Thanks anyway!!
