---
title: Troubleshooting Common OTP SMS API Issues
description: "Encountering hiccups with the SMSGatewayCenter [**OTP SMS API**](https://www.smsgatewaycenter.com/developer-api/generate-otp/)? Don’t worry! This guide tackles common issues and offers solutions to keep your authentication process smooth. ## **Common Issues and Fixes** - **OTP Not Delivered**: - **Check**: Ensure `mobile` format is correct…"
url: "https://www.smsgatewaycenter.com/blog/kb/troubleshooting-common-otp-sms-api-issues/"
updated: "2025-04-15"
category: API
---

# Troubleshooting Common OTP SMS API Issues

Encountering hiccups with the SMSGatewayCenter [**OTP SMS API**](https://www.smsgatewaycenter.com/developer-api/generate-otp/)? Don’t worry! This guide tackles common issues and offers solutions to keep your authentication process smooth.

## **Common Issues and Fixes**

- **OTP Not Delivered**:

- **Check**: Ensure `mobile` format is correct (e.g., `91xxxxxxxxxx`) and senderId is approved.
- **Fix**: Verify DLT registration and test with a new number.

- **Error Code 952 (OTP Already Verified)**:

- **Check**: Response shows `reason=OTP token is already verified`.
- **Fix**: Use `renew=true` to generate a new OTP or ensure single-use logic in your app.

- **cURL Errors**:

- **Check**: Look for `cURL Error #` in the response.
- **Fix**: Confirm internet connectivity and update cURL settings (e.g., `CURLOPT_TIMEOUT` to 30).

- **Slow Delivery**:

- **Check**: High traffic or invalid `callback` URL.
- **Fix**: Optimize your server response time and validate the callback URL.

**Tips**

- Log API responses for debugging.
- Test with the Postman collection from our documentation.
- Contact support if issues persist beyond these steps.

**Support**
Stuck? Email contact @ smsgatewaycenter.com or dial +912228657726 for help.

### More Related Articles

- [How do I secure my API keys in a production environment?](https://www.smsgatewaycenter.com/blog/kb/how-do-i-secure-my-api-keys-in-a-production-environment/)
- [What should I do if my API request times out?](https://www.smsgatewaycenter.com/blog/kb/what-should-i-do-if-my-api-request-times-out/)
- [Solving Common Verify OTP API Problems](https://www.smsgatewaycenter.com/blog/kb/solving-common-verify-otp-api-problems/)

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