As of December 15 2021, we are aware of issues with Vietnamese mobile operators, which are disabling the possibility to receive 2FA messages from NEAR Wallet.
Most possibly you have received an error like this:
We are sorry for any inconvenience caused. The team is working on finding a solution that will re-enable the service. Unfortunately, this is a massive issue that requires a lot of work from the team so we cannot provide any ETA at this moment.