NTP doesn't sync

Question

I'm using Meinberg NTP to sync the time in a VPS. The clock refuses to sync - there's a ~30s shift comparing to other servers. Also ntpq -p is continuously showing zeros for reach, delays and jitters, which means something's wrong...

Actions I've taken which didn't help:

• Restarted the NTP service using a script that comes with Meinberg NTP
• Added port 123 for UDP and TCP as an exception port to Windows Firewall
• Added Meinberk NTP executables as an exception program to Windows Firewall
• Completely disabled Windows Firewall
• validated iburst appears after each server listed in the configuration file
• Restarted the server

The OS is a Windows Server Standard SP2 32bit.

What did I miss?

UPDATE 1

Here's ntpq -p result:

     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 voxl-nyc-21.ser .INIT.          16 u    -   64    0    0.000    0.000   0.000
 sola-sea-04.ser .INIT.          16 u    -   64    0    0.000    0.000   0.000
 207.32.191.59   .INIT.          16 u    -   64    0    0.000    0.000   0.000

UPDATE 2
Turns out that in addition to the Windows Firewall, our VPS provider has blocked all UDP communication to our VPS instance. After opening UDP port 123 it worked flawlessly.

Answer 1

Now it seems you're not communicating with your peers. Either they're not up, not reachable, or a firewall or similar device is blocking UDP port 123.

207.32.191.59 appears to be a working stratum 2 server to me, so if the machine otherwise has working Internet access, I'd bet on a firewall.