Is there an NTP server I should be using when using Amazon's EC2 service to combat clock drift?

I’m using AWS and am on an EC2 server …

[dalvarado@mymachine ~]$ uname -a
Linux mydomain.org 3.14.33-26.47.amzn1.x86_64 #1 SMP Wed Feb 11 22:39:25 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

My clock is off by a minute ro so despite the fact that I already have NTPD installed and running

[dalvarado@mymachine ~]$ sudo service ntpd status
ntpd (pid  22963) is running...

It would appear ntp packets are blocked or there is some other problem because I get this error …

[dalvarado@mymachine ~]$ sudo ntpdate pool.ntp.org
 2 Apr 16:43:50 ntpdate[23748]: no server suitable for synchronization found

Does anyone know with AWS if there’s another server I should be contacting for NTP info or if there are other additional configurations I need?

Thanks, - Dave