Hi there!
You can do as follows in order to solve your problem:
1. Run the ntpq command and check whether the value of reach is 0.
2. Configure the network again, ensure that the NTP server is reachable.
3. On HMM Web, choose System Management > System Settings > Timezone & NTP and check whether the poll internals are too long. You are advised to use the default minimum poll interval 4 (00 : 00 : 16) and the default maximum poll interval 6 (00 : 01 : 04).
4. Reset the poll internals to proper value.
5. Half an hour later, check whether it is solved.