Key Takeaways
- Scheduled SMS troubleshooting starts with clock, device, then plan — not a rewrite of the feature page.
- UTC vs local is the most common “it sent at 3am” bug.
- A Dozed phone holds the queue until OEM lets the app run. That is not a cron bug.
- Scheduled SMS is Starter and up. Free/Developer send now, they do not add a campaign clock.
- Free/Developer pause at SMS allowance; a schedule will not override an exhausted cap.
- You still need operator credit on the SIM when the window opens.
The job fired. The SIM did not.
Android SMS gateway scheduled SMS troubleshooting is the gap between a green “scheduled” chip and a message that actually left a radio. The feature page explains campaigns. This spoke is why they miss: clocks, OEM, pairing, allowance, airtime.
Product: scheduled SMS. Quiet hours: quiet hours. Live params: Developer Center.
“If the phone was in a drawer at 08:00, the schedule succeeded. The radio did not.”
Failure matrix
| Symptom | Likely cause | Check |
|---|---|---|
| Sent 6 hours off | UTC job vs local contact | IANA zone on the row; DST |
| Chip green, zero DLR | Device offline / Doze | Offline alerts |
| Nothing after plan change | Free/Developer allowance pause | Volume used vs cap |
| Fails only on one SIM | Empty voucher / bar | USSD / operator app — not our invoice |
| Schedule option missing | Free or Developer SKU | Starter and up for campaign clock |
Timezone and DST
Store zones, not offsets. A contact who flies does not update Excel. Timezone how-to. IANA: time zone database.
Offline, Doze, pairing
Re-pair after OEM updates. Exempt the app from battery optimization. Battery, setup. Two-way YES/NO at the scheduled instant still needs the device online.
Plan and allowance
Scheduled SMS is Starter and up. Platform volume on those plans is uncapped like Developer is not; devices still meter (2 / 5 / 15). Free 300 lifetime and Developer 25,000/year pause — a calendar entry cannot spend past the cap. Operator credit is separate. Pricing.
Checklist
- TZ on the contact, not “company HQ.”
- Canary at the next window on a staff handset.
- Device charged, paired, OEM-exempt.
- Voucher funded.
- Plan actually includes scheduling.
Next steps
Feature page, DLR, queue architecture.
Related product pages
Jump to the live product docs for this topic—not another long-form article.
- scheduled SMS campaignsSend later windows
- SMS API documentationLive endpoint reference
- device and SMS volume pricingPlans and allowances
- Android SMS gateway product guideDefinition, product, and how to buy
