Messages sent to US numbers will not be delivered if they are sent from numbers that are not associated with an approved A2P 10DLC Campaign. This guide will help you determine if you have completed registration for A2P 10DLC. To initiate or continue an A2P 10DLC registration, visit your console here. Find out how to register using this guide.
For a step-by-step walkthrough, check out this video on resolving Error 30034.
You are sending messages to the US using a US 10DLC number that is not associated with an approved A2P 10DLC Campaign.
Associate your US 10DLC number with a registered A2P Campaign by adding it to the corresponding Messaging Service via the Twilio Console or API. Find out how to register using this guide.
Alternatively, you can also use a different number that is already associated with an approved A2P Campaign to send messages in the US.