If you have selected Time Zone and configured NTP server correctly, after press Get GMT, correct time will be obtained.
It won't lost even you reboot the router. It may takes a few minutes to obtain the correct time if you can access internet.

M Diamond wrote

If you have selected Time Zone and configured NTP server correctly, after press Get GMT, correct time will be obtained.
It won't lost even you reboot the router. It may takes a few minutes to obtain the correct time if you can access internet.

If you are speaking of the time, this is not true.


Here is a snap of "Time Settings Help" page:
[CODE]
Note:
[snip]
2. The time will be lost if the Router is turned off.
3. The Router will automatically obtain GMT from the Internet if it is configured accordingly.
[/CODE]

I confirm that time is lost after rebooting (but Time Zone is saved of course).

My problem is that even after 20 minutes with working internet access, the router hasn't uptime itself, for example:
[CODE]1st day 00:21:48[/CODE]

I have no specific servers configured for NTP and if I click by myself on the button it is working (time is get).

Something specific in my conf: my internet access is only 3G/4G: GMT call may be missing if internet is only by this way?

If you manually input time and date, it will lost after reboot.
But if you use get gmt(from pc or NPT server), it won't lost after reboot.