You sent a message (message SID: SMXXXXX) to a mobile number in a country that requires Alphanumeric Sender ID pre-registration. Our records indicate that you do not have a registered Alphanumeric Sender ID for this country. This can result in lower delivery quality.
If you are sending transactional SMS (like OTP/auth codes, account-related alerts) you should pre-register for the best possible delivery quality.