Duo SMS Codes are no longer supported for logins to NC State Services through Duo. You are required to set up a supported Duo login method.
SMS Codes can be used to access the Duo Device Management page to allow users to self-service adding other supported methods.
Note: SMS (Text) passcodes rely heavily on cellular network coverage and may not arrive instantaneously. Requesting a new passcode will invalidate all previous passcodes. It is recommended to wait to receive the code before requesting additional ones. Passcodes are valid for 10 minutes before expiring.