Android
Set Time Manually on Android auf Android
Android gets its clock from the mobile network or a connected Wi-Fi access point whenever the Set time automatically option is active. That is why typing a new value into the time field either gets rejected or gets overwritten again a few seconds later.
To set the time yourself, the automatic sync has to be disabled first. Go to Tap on Settings ➔ Tap on System ➔ Tap on Date & time ➔ Turn off Set time automatically. Once that switch is off, the time field becomes editable. Tap on Tap on Time, scroll or type the correct hour and minute, then confirm with Set the Time and tap on OK.
This is the right fix when your phone shows the wrong time because of a weak or delayed network signal, when you are on a device without a SIM, or when you deliberately want to test how apps behave at a different time. It is not the right fix if the time is only off by a few seconds due to normal network drift, or if the wrong time zone is the actual cause — in that case check the time zone setting instead of switching off the sync.
Keep in mind that a manually set clock will not correct itself after this. If the phone drifts or you travel across time zones, you need to open the same menu again and either update the time by hand or turn Set time automatically back on.