Common Bulk SMS Problems & Their Solutions

What Is DLT Registration?

1. DLT Registration & Template Rejections

Problem:
Many senders struggle with DLT registration, incorrect headers, template mismatches, or rejections due to non-compliant content.

Solution:

• Use only registered headers and approved templates.
  
  
• Avoid promotional/blocked keywords.
  
  
• Maintain the exact template format—don’t change variables or punctuation.
  
  
• Choose a Bulk SMS provider that offers DLT support and template guidance.

2. Low Delivery Rates

Problem:
SMS not reaching end-users due to operator filters, outdated databases, or template mismatches.

Solution:

• Use proper DLT-approved templates.
  
  
• Avoid sending SMS to non-DND numbers during restricted hours.
  
  

3. Delayed SMS Delivery

Problem:
Messages reach late, affecting OTPs, alerts, and time-sensitive notifications.

Solution:

• Use premium or priority routes for OTPs.
  
  
• Check if the template or sender ID is blocked.
  
  
• Monitor gateway uptime provided by your SMS provider.

4. Delivery Reports (DLRs) Not Updating Properly

Problem:
Users often see pending or inaccurate delivery reports due to operator delays or system sync issues.

Solution:

• Ensure your SMS provider has synchronized reporting with operators.
  
  
• Check API logs to cross-verify the status.
  
  

5. Incorrect Message Formatting

Problem:
Messages break, special characters appear, or text gets converted into Unicode without intent.

Solution:

• Paste the DLT-approved template exactly as it is into the SMS panel/API without changing variables, punctuation, or spacing.
  
  
• After pasting, ensure there is no hidden formatting like bold text, smart quotes, or special symbols.
  
  

6. Technical Issues with APIs

Problem:
API errors, authentication failures, or missing parameters affect sending.

Solution:

• Re-check your API parameters (sender ID, template ID, API key).
  
  
• Ensure you are using the correct API URL/route shared by your SMS provider.
  
  
• Test with a small sample before sending large volumes.
  
  
• Check API logs in your panel to identify errors.

7. Database Quality Issues

Problem:
Invalid numbers, outdated contacts, and duplicate entries reduce delivery rates and increase cost.

Solution:

• Remove duplicates before uploading.
  
  
• Use only active and verified mobile numbers.
  
  
• Maintain your lists in an updated Excel/CSV file.

8. No Tracking or Analytics

Problem:
Users can’t measure performance due to missing campaign analytics like delivery rate, click-through, or bounce data.

Solution:

• Use the reporting section in your SMS panel to check real-time delivery.
  
  
• Review analytics such as delivery %, failures, and clicks.
  
  
  

9. Regional Language Rendering Issues

Problem:
Regional language SMS (Hindi, Tamil, Telugu, etc.) may appear as boxes or unreadable symbols on user devices.

Solution:

• Always choose Unicode mode before sending regional text.
  
  
• Test the SMS preview on 2–3 devices.
  
  
• Keep regional language text simple (avoid special characters).

10. High Traffic Congestion

Problem:
During festival seasons, flash sales, or peak hours, SMS queues get overloaded causing delivery delays.

Solution:

• For OTPs or urgent alerts, use priority/premium route (ask provider).
  
  
• Split high-volume campaigns into smaller batches for better speed.

Conclusion

Most Bulk SMS issues can be easily avoided when clients use the correct templates, maintain a clean database, and choose the right sending route. By following these simple best practices, clients can ensure faster delivery, fewer failures, and smoother SMS campaigns every time. Choosing a reliable SMS provider with strong routing, DLT support, and real-time reporting reduces 80% of these issues.