By default IP Office systems are configured to obtain time from its Voicemail Pro server which obtains that time from the Windows server on which it is installed. Obviously this option cannot be used when the voicemail server is running on a Unified Communications Module since the module gets its time from the IP Office. To support the module, the system must either use an external SNTP time server or to have its time and date set manually.
To change the time settings:
1.Start IP Office Manager and receive the configuration from the IP Office system.
2.Select 
System and select the System tab.
3.Change the Time Setting Config Source value as follows:
•To Use an External Time Server
Change the setting to SNTP. IP Office Manager displays the additional fields for setting the address of the time server or servers.
•To Set the Time Manually
Change the setting to None. The system's time and date are now set through the menu of an Avaya phone user who has System Phone Rights. Refer to the IP Office Manager help for details.
4.Click on the 
save icon to send the configuration back to the IP Office.