Hi,
The 2FA auth works good, using in my case the microsoft authenticator. However: when I select the checkbox “don’t ask again on this device for 30 days”, the entered code is dismissed as WRONG, and when I de-select the checkbox (still with the same 2FA code) and click again, the code is accepted. 
Before fileing a bugreport: is anyone else seeing the same? (docker vaultwarden 1.34.3 on debian)
The above is observed using the web GUI. The app (that also displays the checkbox) works fine.
Did you checked the logs?
Also, check the `/admin/diagnostics` page, and verify the date/time of the server and the device you use to show the 2fa code. My guess would be the device you use is too far ahead of time, and that is why you got it to work while waiting a bit longer. Or the server is too far back in time, with the same result.