When we receive a delivery receipt for an SMS message from a carrier, we turn that receipt into a simple status so you can see whether your message arrived and, if it didn't, why.

A message that isn't delivered is called a bounce, and every bounce is either hard or soft.

A hard bounce normally indicates a permanent issue with message delivery to a particular recipient. Re-sending the same message to a hard bounced number is very unlikely to result in a successful delivery.

The recipient's mobile carrier received the message but declined to pass it on. Carriers can decline messages for a number of reasons, so the message won't be delivered as sent.

The message was refused and won't be delivered.

The message couldn't reach the recipient. This typically means the number isn't in service, has been disconnected, or can't receive text messages.

Check that the number you’re trying to send to is correct and still active.

If multiple messages are rejected or refused, contact us and we can review the detailed carrier response with you.

A soft bounce is usually a temporary issue with sending to a particular recipient. It’s quite possible that a later send to the same recipient is successful.

Delivery is attempted during a set window called the validity period. The message couldn't be delivered before it closed, for example because the phone was off or out of coverage the whole time.

The recipient's phone had no room left to receive new messages.

The carrier's message centre, the system that delivers texts to phones on its network, wasn't able to send the message.

The recipient's mobile account didn't have enough credit, which can happen with pay-as-you-go plans.

The carrier never confirmed whether the message was delivered.

Carriers normally send a delivery receipt saying whether a message arrived. If that receipt never comes, we mark the message NoResponse once: