8f4ba621_oice__VoIP__and_Text_Messaging__Description
[ErrorCode] 30006 [ErrorMessage] Landline or unreachable carrier [Description] 
The destination number is unable to receive this message. Potential reasons could include trying to reach a landline or, in the case of short codes, an unreachable carrier.
Twilio Cloud Communications - APIs for Voice, VoIP, and Text Messaging