Fix a bug about NTP Sync only after 6 hours if first time fail

Hello,

With the recent update 7.40, the option to use an internal NTP server on the network, rather than a public external server, has been introduced.
However, I discovered that if the server doesn't respond within a specific time frame, the next attempt (after the first) is made after 6 hours.
This is far too long to wait.

My request is therefore to correct this behavior with two different approaches:

• The retry occurs at a constant interval (for example, every 5 minutes);
• The retry occurs using a variable time window (if it fails the first time, it retries after 1 minute, then after 2 minutes, then after 5 minutes, then after 10 minutes... etc., increasing the time continuously until it is maintained at a constant interval, perhaps every 30 minutes).