error renewing certificate

I have a VNX5300 in which the certificate is expired, I am following the KB to generate a valid certificate through the following steps:

- Using the nasadmin user

- Check the date

- Folder access /nas/http/conf/ssl.crt

- Check the last certificate generated

- I execute the command to display the certificate: /nas/sbin/nas_ca_certificate -display

- With this command you should present all the certificate information including the expiration date, eg

                    Not Before: Dec 16 05:45:57 2010 GMT

                    Not After: Dec 15 05:45:57 2015 GMT

but does not show.

- When trying to renew the certificate by the user root (su) with the command: /nas/sbin/nas_ca_certificate -generate the following error is displayed:

Posterior is performed a rebooting.

When I tried to access the putty again with the user the following message was generated: nas service is not running. root privileges are required to run this command and with a question asked if you would like to switch to the other controller.

If you can help me with these problems.