the service seems to stopped at somepoint. Here is the output:
systemd-timesyncd.service - Network Time Synchronization
Loaded: loaded (/lib/systemd/system/systemd-timesyncd.service; enabled; vendor preset: enabled)
Drop-In: /usr/lib/systemd/system/systemd-timesyncd.service.d
└─disable-with-time-daemon.conf
Active: failed (Result: start-limit-hit) since Tue 2022-06-21 03:05:57 CEST; 4h 17min ago
Docs: man:systemd-timesyncd.service(8)
Process: 1658 ExecStart=/lib/systemd/systemd-timesyncd (code=exited, status=0/SUCCESS)
Main PID: 1658 (code=exited, status=0/SUCCESS)
Status: "Shutting down..."
Jun 21 03:05:56 openhab3 systemd[1]: Starting Network Time Synchronization...
Jun 21 03:05:56 openhab3 systemd[1]: Started Network Time Synchronization.
Jun 21 03:05:56 openhab3 systemd-timesyncd[1658]: Synchronized to time server for the first time Jun 21 03:05:57 openhab3 systemd[1]: Stopping Network Time Synchronization...
Jun 21 03:05:57 openhab3 systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 21 03:05:57 openhab3 systemd[1]: Stopped Network Time Synchronization.
Jun 21 03:05:57 openhab3 systemd[1]: systemd-timesyncd.service: Start request repeated too quickly.
Jun 21 03:05:57 openhab3 systemd[1]: systemd-timesyncd.service: Failed with result 'start-limit-hit'.
Jun 21 03:05:57 openhab3 systemd[1]: Failed to start Network Time Synchronization.
Jun 21 03:05:52 openhab3 systemd-timesyncd[1621]: Synchronized to time server for the first time [xx.xx.xx.xx]:123 (fritz.box).
Jun 21 03:05:53 openhab3 systemd[1]: Stopping Network Time Synchronization...
Jun 21 03:05:53 openhab3 systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 21 03:05:53 openhab3 systemd[1]: Stopped Network Time Synchronization.
Jun 21 03:05:53 openhab3 systemd[1]: Starting Network Time Synchronization...
Jun 21 03:05:53 openhab3 systemd[1]: Started Network Time Synchronization.
Jun 21 03:05:53 openhab3 systemd-timesyncd[1641]: Synchronized to time server for the first time [xx.xx.xx.xx]:123 (fritz.box).
Jun 21 03:05:56 openhab3 systemd[1]: Stopping Network Time Synchronization...
Jun 21 03:05:56 openhab3 systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 21 03:05:56 openhab3 systemd[1]: Stopped Network Time Synchronization.
Jun 21 03:05:56 openhab3 systemd[1]: Starting Network Time Synchronization...
Jun 21 03:05:56 openhab3 systemd[1]: Started Network Time Synchronization.
Jun 21 03:05:56 openhab3 systemd-timesyncd[1658]: Synchronized to time server for the first time [xx.xx.xx.xx]:123 (fritz.box).
Jun 21 03:05:57 openhab3 systemd[1]: Stopping Network Time Synchronization...
Jun 21 03:05:57 openhab3 systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 21 03:05:57 openhab3 systemd[1]: Stopped Network Time Synchronization.
Jun 21 03:05:57 openhab3 systemd[1]: systemd-timesyncd.service: Start request repeated too quickly.
Jun 21 03:05:57 openhab3 systemd[1]: systemd-timesyncd.service: Failed with result 'start-limit-hit'.
Jun 21 03:05:57 openhab3 systemd[1]: Failed to start Network Time Synchronization.
Jun 21 07:26:21 openhab3 systemd[1]: Starting Network Time Synchronization...
Jun 21 07:26:21 openhab3 systemd[1]: Started Network Time Synchronization.
Jun 21 07:26:21 openhab3 systemd-timesyncd[12984]: Synchronized to time server for the first time [xx.xx.xx.xx]:123 (fritz.box).
Jun 21 07:32:55 openhab3 systemd[1]: Stopping Network Time Synchronization...
Jun 21 07:32:55 openhab3 systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 21 07:32:55 openhab3 systemd[1]: Stopped Network Time Synchronization.
Jun 21 07:32:55 openhab3 systemd[1]: Starting Network Time Synchronization...
Jun 21 07:32:55 openhab3 systemd[1]: Started Network Time Synchronization.
Jun 21 07:32:55 openhab3 systemd-timesyncd[13245]: Synchronized to time server for the first time [xx.xx.xx.xx]:123 (fritz.box).
Jun 21 07:32:55 openhab3 systemd[1]: Stopping Network Time Synchronization...
Jun 21 07:32:55 openhab3 systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 21 07:32:55 openhab3 systemd[1]: Stopped Network Time Synchronization.
Jun 21 07:32:55 openhab3 systemd[1]: Starting Network Time Synchronization...
Jun 21 07:32:55 openhab3 systemd[1]: Started Network Time Synchronization.
Jun 21 07:32:56 openhab3 systemd-timesyncd[13264]: Synchronized to time server for the first time [xx.xx.xx.xx]:123 (fritz.box).
Jun 21 07:37:58 openhab3 systemd[1]: Stopping Network Time Synchronization...
Jun 21 07:37:58 openhab3 systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 21 07:37:58 openhab3 systemd[1]: Stopped Network Time Synchronization.
Jun 21 07:37:58 openhab3 systemd[1]: Starting Network Time Synchronization...
Jun 21 07:37:58 openhab3 systemd[1]: Started Network Time Synchronization.
Jun 21 07:37:58 openhab3 systemd-timesyncd[13463]: Synchronized to time server for the first time [xx.xx.xx.xx]:123 (fritz.box).
Jun 21 07:37:58 openhab3 systemd[1]: Stopping Network Time Synchronization...
Jun 21 07:37:58 openhab3 systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 21 07:37:58 openhab3 systemd[1]: Stopped Network Time Synchronization.
Jun 21 07:37:58 openhab3 systemd[1]: Starting Network Time Synchronization...
Jun 21 07:37:59 openhab3 systemd[1]: Started Network Time Synchronization.
Jun 21 07:37:59 openhab3 systemd-timesyncd[13482]: Synchronized to time server for the first time [xx.xx.xx.xx]:123 (fritz.box).
Jun 21 07:46:37 openhab3 systemd[1]: Stopping Network Time Synchronization...
Jun 21 07:46:37 openhab3 systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 21 07:46:37 openhab3 systemd[1]: Stopped Network Time Synchronization.
Jun 21 07:46:37 openhab3 systemd[1]: Starting Network Time Synchronization...
Jun 21 07:46:37 openhab3 systemd[1]: Started Network Time Synchronization.
Jun 21 07:46:37 openhab3 systemd-timesyncd[13808]: Synchronized to time server for the first time [xx.xx.xx.xx]:123 (fritz.box).
Jun 21 07:46:37 openhab3 systemd[1]: Stopping Network Time Synchronization...
Jun 21 07:46:37 openhab3 systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 21 07:46:37 openhab3 systemd[1]: Stopped Network Time Synchronization.
Jun 21 07:46:38 openhab3 systemd[1]: Starting Network Time Synchronization...
Jun 21 07:46:38 openhab3 systemd[1]: Started Network Time Synchronization.
Jun 21 07:46:38 openhab3 systemd-timesyncd[13828]: Synchronized to time server for the first time [xx.xx.xx.xx]:123 (fritz.box).
Jun 21 07:52:58 openhab3 systemd[1]: Stopping Network Time Synchronization...
Jun 21 07:52:58 openhab3 systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 21 07:52:58 openhab3 systemd[1]: Stopped Network Time Synchronization.
Jun 21 07:52:58 openhab3 systemd[1]: Starting Network Time Synchronization...
Jun 21 07:52:58 openhab3 systemd[1]: Started Network Time Synchronization.
Jun 21 07:52:58 openhab3 systemd-timesyncd[14070]: Synchronized to time server for the first time [xx.xx.xx.xx]:123 (fritz.box).
Jun 21 07:52:59 openhab3 systemd[1]: Stopping Network Time Synchronization...
Jun 21 07:52:59 openhab3 systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 21 07:52:59 openhab3 systemd[1]: Stopped Network Time Synchronization.
Jun 21 07:52:59 openhab3 systemd[1]: Starting Network Time Synchronization...
Jun 21 07:52:59 openhab3 systemd[1]: Started Network Time Synchronization.
Jun 21 07:52:59 openhab3 systemd-timesyncd[14089]: Synchronized to time server for the first time [xx.xx.xx.xx]:123 (fritz.box).
Jun 21 08:01:21 openhab3 systemd[1]: Stopping Network Time Synchronization...
Jun 21 08:01:21 openhab3 systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 21 08:01:21 openhab3 systemd[1]: Stopped Network Time Synchronization.
Jun 21 08:01:21 openhab3 systemd[1]: Starting Network Time Synchronization...
Jun 21 08:01:21 openhab3 systemd[1]: Started Network Time Synchronization.
Jun 21 08:01:21 openhab3 systemd-timesyncd[14404]: Synchronized to time server for the first time [xx.xx.xx.xx]:123 (fritz.box).
Jun 21 08:01:21 openhab3 systemd[1]: Stopping Network Time Synchronization...
Jun 21 08:01:21 openhab3 systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 21 08:01:21 openhab3 systemd[1]: Stopped Network Time Synchronization.
Jun 21 08:01:21 openhab3 systemd[1]: Starting Network Time Synchronization...
Jun 21 08:01:22 openhab3 systemd[1]: Started Network Time Synchronization.
Jun 21 08:01:22 openhab3 systemd-timesyncd[14425]: Synchronized to time server for the first time [xx.xx.xx.xx]:123 (fritz.box).
Jun 21 08:05:59 openhab3 systemd[1]: Stopping Network Time Synchronization...
Jun 21 08:05:59 openhab3 systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 21 08:05:59 openhab3 systemd[1]: Stopped Network Time Synchronization.
Jun 21 08:05:59 openhab3 systemd[1]: Starting Network Time Synchronization...
Jun 21 08:06:00 openhab3 systemd[1]: Started Network Time Synchronization.
Jun 21 08:06:00 openhab3 systemd-timesyncd[14603]: Synchronized to time server for the first time [xx.xx.xx.xx]:123 (fritz.box).
Jun 21 08:06:00 openhab3 systemd[1]: Stopping Network Time Synchronization...
Jun 21 08:06:00 openhab3 systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 21 08:06:00 openhab3 systemd[1]: Stopped Network Time Synchronization.
Jun 21 08:06:01 openhab3 systemd[1]: Starting Network Time Synchronization...
Jun 21 08:06:01 openhab3 systemd[1]: Started Network Time Synchronization.
Jun 21 08:06:01 openhab3 systemd-timesyncd[14623]: Synchronized to time server for the first time [xx.xx.xx.xx]:123 (fritz.box).
Jun 21 08:06:03 openhab3 systemd[1]: Stopping Network Time Synchronization...
Jun 21 08:06:03 openhab3 systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 21 08:06:03 openhab3 systemd[1]: Stopped Network Time Synchronization.
Jun 21 08:06:03 openhab3 systemd[1]: Starting Network Time Synchronization...
Jun 21 08:06:04 openhab3 systemd[1]: Started Network Time Synchronization.
Jun 21 08:06:04 openhab3 systemd-timesyncd[14639]: Synchronized to time server for the first time [xx.xx.xx.xx]:123 (fritz.box).
Jun 21 08:06:04 openhab3 systemd[1]: Stopping Network Time Synchronization...
Jun 21 08:06:04 openhab3 systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 21 08:06:04 openhab3 systemd[1]: Stopped Network Time Synchronization.
Jun 21 08:06:04 openhab3 systemd[1]: Starting Network Time Synchronization...
Jun 21 08:06:04 openhab3 systemd[1]: Started Network Time Synchronization.
Jun 21 08:06:04 openhab3 systemd-timesyncd[14658]: Synchronized to time server for the first time [xx.xx.xx.xx]:123 (fritz.box).
Jun 21 08:06:07 openhab3 systemd[1]: Stopping Network Time Synchronization...
Jun 21 08:06:07 openhab3 systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 21 08:06:07 openhab3 systemd[1]: Stopped Network Time Synchronization.
Jun 21 08:06:07 openhab3 systemd[1]: Starting Network Time Synchronization...
Jun 21 08:06:08 openhab3 systemd[1]: Started Network Time Synchronization.
Jun 21 08:06:08 openhab3 systemd-timesyncd[14678]: Synchronized to time server for the first time [xx.xx.xx.xx]:123 (fritz.box).
Jun 21 08:06:08 openhab3 systemd[1]: Stopping Network Time Synchronization...
Jun 21 08:06:08 openhab3 systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 21 08:06:08 openhab3 systemd[1]: Stopped Network Time Synchronization.
Jun 21 08:06:08 openhab3 systemd[1]: systemd-timesyncd.service: Start request repeated too quickly.
Jun 21 08:06:08 openhab3 systemd[1]: systemd-timesyncd.service: Failed with result 'start-limit-hit'.
Jun 21 08:06:08 openhab3 systemd[1]: Failed to start Network Time Synchronization.