IMPORTANT – when the summer time changes (spring and autumn to/from GMT to BST)
you MUST after the change, and before you try to login to any accounts using Google Authenticator,
first resync your mobile phone Authenticator App with the time server!
Make sure you do this – otherwise your accounts get blocked, involving lengthy ID verification procedures in order to unblock them again!
And make sure to do this with ALL mobile phones you have in use for Google Authenticator!
To make sure your app is using the correct time:
Go to main menu on the Google Authenticator app
Select Time correction for codes
Select Sync now
On the next screen, the app will confirm the time has been synced.
You should now be able to use your Authenticator codes to log in to the websites that require the 2FA codes.
Note: this sync will only affect the internal time of your Google Authenticator app. It does not change your device’s Date and Time settings.
This can also be changed by setting your Android or iPhone to automatically update its time.
For iPhone and Android: go to Setting > General, Date and time > Automatically correct time.