Samsung
Set Time Manually auf Samsung
Samsung phones normally pull the current time from the mobile network. That works reliably in most areas, but a weak signal, a carrier outage or a SIM swap can cause the displayed time to drift or freeze at an old value.
To fix this, disable the automatic sync and enter the time yourself. Go to Tap on Settings ➔ Tap on General management ➔ Tap on Date and time ➔ Turn Off Automatic date and time.
With automatic sync off, tap Tap on Set time, scroll to the correct hour and minute, then confirm with Set the Time and tap Done.
Manual time only makes sense as a temporary fix. If your phone regularly shows the correct time through the network, leave automatic date and time enabled instead of correcting it by hand every day.
Note that turning off automatic time does not automatically disable automatic time zone. If you travel, check that setting separately or your clock may still shift unexpectedly.

