NTP not synchronizing

I Have a new deployment of ePMP 2.4Ghz. Cant seem to get NTP working on any of the SM's I have about 50 deployed so far with firmware ranging from 2.3.4 through 2.4 beta. I've tried nist time servers, windows servers on the same subnet. verified firewalll rules for udp 123. but none of the SM's ever sync.  I have placed a pc behind an SM and can get it so sync with either... just not the SM's. Ideas?

do you have any DHCP options being sent? all of our radios get NTP information from DHCP option 4 (or 42) both are configured.     we are running 2.3.4