It works fine now. Steps are:
in whmcs server (with cpanel)
1-check your csf to open 7777 and 7778 ports
2-Add your kloxo server ip , to csf white list
3-Check
in whmcs check SSL
in kloxo.
1-Check that all works fine, add a domain and test it.
2-Run /scripts/upcp
3-Check if curl is enabled or not ( in case it does not affect it)
Then it should work fine then.
Thanks !