Per local regulations, only Person-to-Person (P2P) messages may be sent via Malaysian domestic long codes. Due to local carrier restrictions, Twilio has observed increased filtering towards Malaysian carriers when Application-to-Person messaging is originated from Malaysian mobile numbers. 

Mobile marketing campaigns, pin code verification, etc are considered A2P (Application to Person) traffic and Twilio recommends sending such traffic using a global SMS-capable phone number (e.g., US or Canadian local number) instead. 

For more details, please review Twilio's current Malaysia SMS Guidelines and Malaysia Regulatory Guidelines.