We have encountered a critical issue regarding our user authentication process and need your urgent assistance. Currently, all of our users are failing to receive the OTP SMS sent via Web3Auth during the login process.
Upon checking our Web3Auth Developer Dashboard, we noticed a highly unusual behavior: despite numerous login attempts by our users, the successful login count is strictly showing as “0”.
Hi @Jiwon_Seo thanks for reaching out. Could you please double - check the following:
Confirm phone numbers are being sent in E.164 format (e.g. +15551234567).
Check Web3Auth (or your SMS provider) delivery logs for per-message status and error codes — look for permanent blocks vs transient failures.
If you’re on Web3Auth’s default SMS provider, try a more robust provider (Twilio, AWS SNS, MessageBird) for a subset of users to compare deliverability.
Add server-side logging for every send attempt: timestamp, provider response, status code, and any message-id returned.
Implement exponential backoff for retries and avoid immediate repeated sends that can trigger carrier protections.
Consider a fallback (email OTP or social login) while you investigate.
What would help the support team investigate (please provide if available)
Platform: Web / Mobile (iOS/Android)
Which SDK/integration you’re using (Web3Auth passwordless/phone verifier, or other) and SDK version number
Are you using Web3Auth’s default SMS provider or a custom SMS gateway? If custom, which provider?
Examples of countries/carriers affected (are issues concentrated in specific regions?)
Timestamps (UTC) and masked sample phone numbers for a few failed attempts
Server and provider response logs for failed sends (or screenshots of provider dashboard showing failures)
Code snippets for your OTP init/send/login flow (initialization & login snippets)
Any browser console logs or mobile logs at the time of failures
Relevant docs & next steps
Web3Auth docs (general): https://docs.web3auth.io/ — check the OTP / phone-passwordless sections and any provider configuration.
If you find provider-level error codes in logs, share them here and we can interpret specifics (e.g., 429, 4xx carrier block, 5xx gateway error).
If you want, share the platform, SDK version, whether you use Web3Auth’s SMS provider or a custom SMS gateway, and one small code snippet (init/login). If you can attach a screenshot of provider logs or the browser console showing the failure, that’ll speed things up.