There are a number of possible reasons why a KakaoTalk Brandmessage message is not delivered to a KakaoTalk user and/or returns an  error:
 
- The user has not added the channel as friends. KakaoTalk Brandmessages can only be sent to user who has added the channel as friends. To be a friend of a KakaoTalk channel, go to the Channel tab and click the Add Channel button to the right of the KakaoTalk channel name:
 
  
 
 
- The user has not used KakaoTalk for a while.
 
 
- The user has deactivated KakaoTalk push messages.
 
 
- The user does not have the minimum KakaoTalk version or unsupported device.
 
- The message was sent after 9PM and before 8AM Korean time.