⚠️ Some Common OTP & Email Authentication Issues and How to Fix Them?
While OTP and email verification systems are highly effective for securing user access, technical and delivery-related issues may occasionally occur. Below are the most frequent problems and how to resolve them.
📩 1. OTP/Email Not Delivered
Causes:
- Incorrect phone number or email entered
- Recipient is on DND or blacklist
- Slow carrier or SMTP server response
- Emails landing in spam/promotions folder
Solutions:
- Implement input validation before submission
- Retry OTP/email with a cooldown timer (e.g., 30 seconds)
- Whitelist sender domain or SMS sender ID
- Use verified email domain and proper SPF/DKIM records
🔄 2. OTP Expired Before Use
Causes: Users wait too long or network delays slow down delivery.
Fix: Set OTP validity to 2–3 minutes and allow limited resend attempts.
❌ 3. "Invalid OTP" Even After Correct Entry
Causes: Mismatch between entered OTP and server-stored OTP or incorrect OTP session handling.
Fix:
- Ensure server correctly maps OTP to user session or transaction ID
- Log and verify OTP lifecycle (sent → stored → validated)
📵 4. Issues with International Numbers
Causes: Some routes do not support international delivery.
Fix: Use Muzztech’s global gateway-enabled API and confirm formatting as per E.164 standard (+91 for India).
🔐 5. API Integration Errors
Symptoms: Server not responding, 401 Unauthorized, JSON errors.
Fix:
- Double-check API key and endpoint URL
- Verify request headers and body format
- Consult our API documentation or contact support
🧪 Developer Tips
- ✔️ Log every OTP/email event with timestamp
- ✔️ Limit retry attempts to avoid brute force abuse
- ✔️ Use different templates for login, signup, and reset flows
- ✔️ Monitor delivery reports from SMS/email gateway
Still stuck? Contact our integration team at support@muzztech.co.in