Hi @Joy_1P yes, here is the full list of what I tried (note that it is working now after the account recovery):
"Tested on 2 different pc devices ubuntu and windows, can still log in mobile app, but even from mobile android chrome trying to log in through the browser gives the same error. Checked https://time.is/ on all devices and times are the same. Tried the time syncing on the authentication app, but it shows it is already synced to google server time. Tried exporting the authentication app accounts directly to the devices, still the same error message"
In the end I tried requesting the account recovery with my admin,
and after he reset the account the 2FA now works.