Stop the Doubt! Delivery report (DLR) shows under Message History
What is Delivery Report?
Delivery report (DLR) is a feature that gives you a feedback on the delivery status of every SMS message submitted. It is sourced directly from the handset through the mobile net carrier of the mobile number the message is sent to.
The DLR helps you stop guesses after you have sent a message, giving you the true picture of the status of the messages sent.
Know This About DLR
- DLR is not available on all networks.
- DLR is not sent for all messages received by the operators.
- Even when the operator supports DLR, the time it takes for it to send report varies between 15 minutes to 48 hours after the message has been sent.
Different Delivery Statuses
Here is the list of the DLR statuses returned by the operators and what they mean.
- SENT
Message was sent to the operator but yet to get any DLR.
- ACCEPTED
Message was accepted by the operator for delivery.
- PENDING
Message has been forwarded to the phone number and possibly delivered but the recipient’s phone is yet to reply the operator with acknowledgement.
- DELIVERED
Message was delivered to cell phone.
- UNDELIVERED
Attempt to deliver message failed, maybe because the handset of the subscriber is out of network coverage when message delivery was attempted or the handset might be switched off. The message might have failed due to suspicion of SPAM on the operator network e.g. use of reserved Sender ID relating to financial institutions or government agencies. The reason may also be due to random unsolicited messages blocked by the operator; or political campaign not permitted by the operator; or same message sent to the same phone number repeatedly over a short time; or the phone number might have been recycled after a period of no activity.
- REJECTED
The message was rejected, maybe because: the subscriber is on the Do-Not-Disturb list; or the provider could have blocked phone numbers in this range; or the message flagged as SPAM (Mass unsolicited messages); or the message flagged as SCAM (Messages with potential intent to defraud, defame or threatens social security); or the network provider is having issues or they are currently upgrading their system.
- ENQUEUE
Message was sent to the operator and forwarded to the cell phone but yet to reply with delivery acknowledgement.
- ENROUTE
Message is being routed for delivery.
- EXPIRED
The SMS Center was unable to deliver the message in a specified amount of time (Message Validity), usually between 15 minutes and 48 hours. In some instances (especially when the operator is under traffic pressure), the operator might expire some messages instantly once it cannot be delivered as at first attempt. Message may also expire because the cell phone was switched off as at the time of delivery.
- UNSUPPORTED
Delivery report is not supported by the route or the operator.
- DELETED
Message was deleted.
- UNKNOWN
The message has been confirmed as undelivered but no detailed information related to the failure is known. An unknown error might have occurred on the operator SMS server, or as a result of portability error.
What are the main reasons for an undelivered message?
There are several reasons why an SMS might fail to be delivered.
Incorrect or inactive number
The mobile number is wrong, inactive or no longer in use.
Wrongly formatted number or message
The mobile number has been incorrectly formatted or is incomplete. Nigeria Mobile numbers can either start 080 or 090 or 081 or 070 or 234 being the international dialling code for Nigeria. Other countries have their number formats too.
The number contains too few or too many numbers.
The message contains unsupported characters.
No mobile phone signal
The mobile phone was out of range for about 48 hours and the message expired.
The mobile was switched off
The phone was switched off and remained switched off until the message expired (after 48 hours)
International roaming disabled
If international roaming is switched off, then some handsets may not receive texts.
Hanging text
Occasionally a message can hang on the network despite the receiving handset having a strong signal. Switching the phone off and on again often resolves this issue. This is becoming increasingly rare but still happens occasionally.