How to Resync Time for Authenticator Codes on Android and iPhone

Authenticator codes that used to work can suddenly start failing after a trip, a software update, or a long period with a dead battery. In many cases the app itself is fine. What has changed is the time on your phone, and time-based codes only work when your device and the service agree on what time it is.

Resyncing the time is a quick fix on both Android and iPhone. This guide walks through the exact settings to check, and what to try next if a fresh sync does not solve the problem.

Quick Answer

To resync time for authenticator codes, turn on automatic date and time in your phone settings, connect to Wi-Fi or mobile data, and restart the phone. On Android go to Settings, System, Date and time, and enable automatic time and time zone. On iPhone go to Settings, General, Date and Time, and turn on Set Automatically, then wait for a fresh code before signing in.

Why Authenticator Apps Need an Accurate Clock

Apps such as Google Authenticator, Microsoft Authenticator, and Authy create codes using a method based on the current time in 30-second windows. The website you are signing in to runs the same calculation on its server. If both sides use the same secret key and the same time window, they produce the same number.

Your phone does not need an internet connection at the moment you read a code, because the calculation happens on the device. It does, however, need a clock that was set accurately. Once that clock drifts, every new code drifts with it. Resyncing simply brings the phone back to true time so the calculation matches again.

Signs that time drift is your problem

• Codes fail on more than one account at the same time.
• Codes worked yesterday and fail today with no account changes.
• Your phone clock looks a minute or more different from another device.
• Codes sometimes work at the start of a countdown and fail at the end.
• The problem started after travel, a manual time change, or a flat battery.

If only one account is affected while the rest work normally, time may not be the cause. That single entry could have been set up incorrectly, or the account may have had two-factor authentication reset on the server side.

How to Resync Time on Android

The exact menu labels differ slightly between phone makers, but the path is similar on most recent Android versions.

1. Open Settings and tap System. On Samsung phones, look for General management instead.
2. Tap Date and time.
3. Turn on Set time automatically. On some devices this is called Automatic date and time.
4. Turn on Set time zone automatically as well.
5. If there is an option to use location to set the time zone, allow it.
6. Make sure the phone is online through Wi-Fi or mobile data.
7. Turn the automatic options off and back on once if the displayed time does not change.
8. Restart the phone.
9. Open the authenticator app, wait for the next new code, and test it on one account.

Google’s help for Android explains that changing the date and time on an Android device is normally handled automatically by the network, which is why leaving those automatic switches on is the safest long-term setting.

Extra checks on Android

If the time still will not update, try a different network and toggle airplane mode on and off to force the phone to reconnect and request fresh network time. A phone with no SIM and no Wi-Fi has no source to sync from, so connect it first.

How to Resync Time on iPhone

1. Open Settings and tap General.
2. Tap Date and Time.
3. Turn on Set Automatically.
4. Check that the time zone shown is the city or region you are actually in.
5. Connect to Wi-Fi or mobile data and give the phone a few seconds to update.
6. If the time does not change, turn Set Automatically off, wait ten seconds, and turn it on again.
7. Restart the iPhone.
8. Open the authenticator app and wait for a completely new code before testing.

If the Set Automatically switch is greyed out, a Screen Time passcode setting or a work or school management profile may be controlling it. In that case you may need to adjust that restriction or ask the organisation that manages the phone. Apple documents this in its support page about what to do if you cannot change the time on your Apple device.

Check location services for the time zone

An iPhone sets its time zone partly through location services. If location is off for system services, the zone may stay stuck on a place you visited earlier. Go to Settings, Privacy and Security, Location Services, System Services, and make sure Setting Time Zone is allowed. Then return to Date and Time and confirm the zone updates.

Resyncing Inside Authenticator Apps

After fixing the phone clock, close the authenticator app fully and reopen it. Older Android versions of Google Authenticator included a dedicated time correction option in settings. If you still see one, run it while online. If not, do not worry: current versions expect the system clock to be correct, so the phone settings above are the real fix.

While you are in the app, confirm you are reading the entry for the right service. It is easy to have similar-looking entries for a personal account, a work account, and an old account. Using the wrong entry looks exactly like a time problem because the code is valid for a different secret key. Our related guide on fixing two-factor authentication codes that stop working covers those account-mix-up checks in more detail.

Testing Your Fix Properly

1. Wait until a new code appears in the app.
2. Check the countdown. If less than ten seconds remain, wait for the following code.
3. Type the code carefully without spaces.
4. Submit it once. Do not submit the same code repeatedly.
5. If it works, test one more account to confirm the fix is general.
6. If it fails, stop and check the date and time zone again before trying more codes.

Repeated failed attempts can cause some services to pause further attempts for a short period. If that happens, wait, fix the clock in the meantime, and then try a single fresh code.

What If Resyncing Does Not Work?

The entry itself may be wrong

If every other account works after the resync, this entry may have been added from an old QR code or reset on the server side. Sign in with a backup code, then set up authenticator access again from the account security page so both sides share a fresh secret.

Your phone date may be wrong, not just the time

Look at the full date. A phone that thinks it is yesterday or tomorrow will never generate a matching code, even at the right hour. Automatic settings normally fix the date and time together, which is another reason to prefer them over manual changes.

You may be using an old device

Many people keep an old phone as a backup authenticator. That phone may sit in a drawer losing time for months. Charge it, connect it to Wi-Fi, resync its clock, and only then judge whether its codes are truly broken.

Common Mistakes to Avoid

• Setting the time by hand to match a clock on the wall. Wall clocks drift too. Automatic network time is far more accurate.
• Testing with a code that is about to expire. Network delay plus a nearly finished countdown can cause a false failure.
• Changing the time but not restarting. Some apps keep running with old state. A restart clears that cleanly.
• Forgetting the time zone after travel. A correct-looking hour with a stale zone can still mean the underlying time is wrong.
• Deleting and re-adding every account at once. Fix the shared clock first. Mass resets create a much bigger recovery job.
• Trying code after code during a lockout. Pause, fix the cause, and make one careful attempt.

Keeping Your Codes Reliable in Future

Leave automatic date, time, and time zone enabled all the time. After flights, connect to local Wi-Fi or mobile data for a minute before signing in to important accounts, and keep backup codes for critical accounts stored safely offline.

Conclusion

Resyncing time for authenticator codes is mostly a two-minute settings job. On Android, enable automatic time and time zone under Date and time. On iPhone, turn on Set Automatically and confirm the zone is right. Restart, wait for a fresh code, and test carefully once. If only one account still fails after that, treat it as an account setup issue rather than a clock issue, and reset that single entry using a backup sign-in method.

Frequently Asked Questions

Do authenticator apps need internet to resync time?

The phone needs a connection to learn the correct time from the network or a time server. Once the clock is accurate, the app can generate codes offline, because the code calculation happens on the device itself.

Why did my codes stop working after travelling?

Travel often changes the time zone, and sometimes the phone keeps an old zone or a manual setting. That can shift the underlying time enough to break the 30-second code windows. Turning on automatic time zone and reconnecting to a local network usually fixes it.

Is there a time sync button inside Google Authenticator?

Older Android versions had a time correction option, but newer versions mainly rely on the phone system clock. If you cannot find a sync button, fix the time in the phone settings instead, then restart and reopen the app.

How long should I wait before testing a code after resyncing?

Wait until the app shows a brand-new code with most of its countdown remaining. Testing in the last few seconds of a window can fail because of normal delay between typing and the server checking the code.

Will resyncing time log me out of my accounts?

No. Changing time settings does not remove authenticator entries or sign you out of the app. It only corrects the clock. Your accounts stay set up exactly as before, but their codes should start matching the server again.