Here's a list with the top reason why your SMS are being skipped. If you want to learn more why a specific message was not delivered reach to our support channel.
Message Delivery - Unknown error: The destination carrier has returned a generic error message.
Message Delivery - Unknown destination handset: The destination carrier is reporting the To number is unknown, or no longer in service.
Message Delivery - Unreachable destination handset: The destination carrier is reporting the 'To' number is unreachable - the device is likely powered down, out of the service area, or may not accept your messages.
Message Delivery - Carrier Violation: The destination carrier is filtering out your messages for delivery.
Message Delivery - Message blocked: Your message has been blocked from reaching the destination.
Message Delivery - Landline or unreachable carrier: The destination is a landline phone, or the destination carrier can't be reached.