Force Rhel to sync with NTP server?

I have a rhel 6 host that I am trying to point to a juniper ssg firewall as an ntp server. It isnt working quite right and I found the below article from Juniper which details the exact issue I am seeing. Question for you all is there a way to force it to sync and remain synced with this firewall?

https://kb.juniper.net/InfoCenter/index?page=content&id=KB24784