Redmine

I have installed the plugin Redmine CAS,https://github.com/ninech/redmine_cas, in redmine 2.2.1 with ruby on rails 1.9.2. After configuring the plugin when I access redmine get the following error:

RuntimeError (The CAS authentication server at https://HostCAS:8443/cas-w
eb/login/proxyValidate?service=http%3A%2F%2FHOSTREDMINE%3A3000%2F&ticket=ST-771-
PQxjyd5Wns0zVJvdAgre-cas01.example.org responded with an error (#<Net::HTTPFound
302 Movido temporalmente readbody=true>)!):
app/controllers/application_controller.rb:163:in `check_if_login_required'

Do I need to install the certificate of cas?
I have not found any information about this error.

Thanks in advance.