An SMS campaign can finish dispatching while some messages are still waiting or have failed. Investigate the individual result before sending again. The campaign name, sender, recipient and message reference help you distinguish a delayed report from a problem that needs correction.
This guide follows a practical investigation using Momo Business campaigns, contact groups and sender identities. For initial setup, start with sending SMS and WhatsApp campaigns.
Separate sending from delivery
Queued or processing means work is waiting or underway. Sent generally means the sending stage succeeded; it is not proof that the recipient read the message. Delivered reflects the delivery information available from the provider. Read status is channel-dependent and should not be expected for ordinary SMS.
Open Campaigns, select the campaign and inspect individual message results. Compare their timestamps and any reported errors. A customer's report that nothing arrived is useful context, but check the original message before creating another send.
Check the sending identity
Confirm which identity the campaign actually used. An approved sender ID, a suitable number and a short code are different options, and availability depends on the workspace's setup.
If a sender ID is missing or rejected, inspect its approval, country and operator results in Sender IDs. A submitted request is not approval, and partial approval does not cover every destination. Follow the sender ID guide if the request is incomplete.
Do not replace the sender with a similarly named identity without checking which business and country it belongs to. Keep a controlled test recipient available to confirm the sender name displayed on the handset.
Check the audience and message
Open the selected contact group and inspect the affected recipient's complete number, including the country code. Compare it with a verified contact detail. A formatted number can still belong to the wrong person, so resolve that mismatch before resending.
Check whether the group contains duplicate people under differently entered numbers. Review opted-out recipients before each campaign: the subscription checkbox alone does not currently exclude contacts from messaging campaigns. Use the applicable blocking controls and prepare the audience deliberately.
For personalized messages, compare the exact field keys with the contact values. A blank order reference is a content problem even if delivery succeeds. Test long names and missing custom fields before the full send. The Contacts guide explains imports and field preparation.
Look for a shared cause
| What you see | What to check next |
|---|---|
| Many recipients fail with the same error | Sender approval, connection, provider result and available service credit |
| Only one or a few numbers fail | Country code, verified number, destination and individual error |
| Messages progress slowly | Send interval, campaign state and provider limits |
| Campaign stops processing | Displayed pause reason, wallet balance and schedule |
| Message arrives with missing details | Contact values and personalization keys |
| Customer reports a duplicate | Earlier attempts, campaign restart and manual sends |
Use the actual error to guide the next step. Changing several unrelated settings at once makes it harder to identify the cause.
Retry without repeating the whole audience
Check which messages completed before retrying. Restart starts fresh sends and can contact recipients again; it is not a failed-only retry action. Pause or cancel outstanding work when offered if the content or audience is wrong, then inspect the saved state. These actions cannot retract delivered SMS.
After correcting a shared issue, send a controlled test and inspect its result before deciding how to handle the remaining audience. Keep the original campaign and message references when requesting help so the investigation follows the existing history.
A useful support summary includes the time, sender, destination country, reported error and affected message reference. Share customer numbers and message content only through the appropriate private support channel.