Final answer:
To find out who didn't receive an SMS when you're notified of a delivery failure, open the relevant message in the app and look for indicators such as an error icon. Clicking this icon typically reveals a list of contacts who did not receive the message. Some messaging applications or services also provide detailed delivery reports.
Step-by-step explanation:
When you receive a notice that an SMS message you sent to multiple people did not go through to all recipients, the method to determine who didn't get the message varies depending on your device and messaging application. Most modern smartphones and messaging apps will show a 'failed' status next to the message or provide a list of recipients for whom the message was not delivered. Here are some steps you can take to check:
- Open the messaging app and navigate to the conversation where you sent the bulk SMS.
- Tap on the message that was indicated as not delivered to some recipients.
- Often, you will see a red exclamation point or an error icon indicating a delivery issue.
- Click on the error icon, and it should show you a list of contacts to whom the message didn't send successfully.
- If the app supports detailed delivery reports, check the report for each recipient's status.
Some carriers or apps allow you to request a delivery report for each message sent, which will also notify you if the message wasn't delivered to specific contacts.