With a valid network connection, a valid NTP time server setting (including by default), and the correct time zone setting, you should never see incorrect time.
Possible Causes

The most common reason results from the wrong time zone setting. Configure the time zone in the device’s web server (see the bullet point above under “General Questions” on how to access the web server).

The second most common cause results when the device cannot find the NTP server, or a lost network connection, in which case the clock will free-run, and thus drift over time. You can check the device’s logs to check for this situation (see question below). You should also see #1 above on NTP settings.

If you use ClockWise Campus or a PC as your NTP server, verify and correct the computer clock if needed. The updated time will reflect on associated endpoints within a minute.

If the device is running older firmware (1.4.0001 or older), and the NTP server rejects the NTP request, the incorrect time can display based on the last data exchange with the failing NTP server. Often this failure mode will show up as the device reporting the incorrect time and resetting to the same incorrect time every 20-60 minutes. Update the device firmware to the latest version to fix this and/or change your NTP servers to use a known good server. We recommend the following NTP servers:

0.anetd.pool.ntp.org

1.anetd.pool.ntp.org

2.anetd.pool.ntp.org

3.anetd.pool.ntp.org

It generally defaults to once an hour, but you can set the rate on the Device Settings → General Settings web server page.

You can synchronize a device’s internal clock in a number of ways, including use of an NTP server, as well as registration to some application servers (such as InformaCast), and some SIP servers.
Direct from the factory, the unit arrives programmed to receive its time from an Internet NTP time server, and its time zone is set to Chicago time.

The time zone must be set appropriately for the location of the unit. Some standard timezone names available in the USA include the following:

EST5EDT

EST

CST6CDT

MST7MDT

MST

PST8PDT

HST

When not using a configuration file, find the time zone setting on the Device Settings –> General Settings page, along with the NTP server configuration.

When “registering” your unit with certain software packages (see Device Settings –> Server Settings page) the unit’s time will set automatically via the server registration process, and this time may take precedence over the use of NTP for configuring the time. The registered server’s time is considered of a higher precedence because synchronized events coming from the server should occur at a specific time at the endpoint.

Without a server configured as described above, or when your server type does not set the time on the unit, we advise configuration of the primary (and secondary) NTP server settings. The device may automatically find additional NTP servers via DHCP option 42. In the case of available servers via DHCP option 42, you do not need to configure the unit for other NTP servers, unless you prefer other NTP servers.

If the network configuration does not allow access the internet, you may need to provide internal (i.e. intranet-based) NTP servers for use by the unit. You can configure ClockWise Campus as an NTP server if convenient, especially in cases where MS Windows time does not always closely synchronize with the outside world. When using ClockWise Campus as an NTP server, Windows may block use of the standard NTP port, in which case you can use a secondary port available via the ClockWise Campus settings page. You must use an explicit port number (by appending a colon and the port number after the NTP server address) in the unit’s settings when using a non-standard NTP port.

You may also use a SIP server to set the time on the unit. Some SIP servers will send the time in the SIP registration response. However, the time from the SIP server is not available at a sub-second accuracy as with NTP, and therefore the time from NTP servers configured will take precedence over the use of SIP server time.