Sumsub experienced a minor incident on February 24, 2025 affecting API and MobileSDK and 1 more component, lasting 7h 2m. The incident has been resolved; the full update timeline is below.
Affected components
Update timeline
- investigating Feb 24, 2025, 10:32 AM UTC
We are currently experiencing temporary SMS delivery issues affecting some users. Our team is actively investigating the issue and working with SMS service providers to resolve the issue as quickly as possible. We apologize for any inconvenience this may cause and appreciate your patience. Updates will be provided as soon as more information is available. Thank you for your understanding.
- monitoring Feb 24, 2025, 02:27 PM UTC
We are happy to report that SMS delivery issues have been resolved and we are now actively monitoring the system to ensure stability. Thank you for your patience. Please reach out to Sumsub Support if you experience any further issues.
- resolved Feb 24, 2025, 05:34 PM UTC
After several hours of extensive monitoring and testing, issue is confirmed to be resolved. Our Team has conducted additional series of checks and tests to ensure the delivery remains stable. If you have any further issues or questions, please contact Sumsub Support!
- postmortem Feb 24, 2025, 05:37 PM UTC
## **Incident Timings** **Start time:** 23 Feb 07:00 UTC **End time:** 24 Feb 14:00 UTC ## **Incident Summary** Some of our clients reported a decline in SMS delivery rates. After switching to the fallback SMS sending method, delivery remained stable for some time but began declining again after several hours. As a result, a small portion of applicants were unable to complete verification because they did not receive SMS notifications. Once the underlying issue was identified and resolved, our team ensured that no further action was required from clients. Affected applicants can complete the verification process by simply retrying the SMS step. ## **Root Cause** A significant volume of untracked SMS messages caused by a technical issue. These messages were sent in unusual way, allowing to bypass both our system’s and the SMS provider’s rate-limiting mechanisms. This resulted in an unusually high spike in message traffic, leading to message queues, with some messages timing out and not being delivered. ## **Action Plan** As a result of this issue, our Team has identified several key areas for improvement: 1. **Enhance Monitoring & Visibility:** Improve alerting for SMS delivery 2. **Prevent Recurrence:** Enhance rate limiting and throttling 3. **Collaborate with SMS providers:** Coordinate with our SMS service providers to improve anomaly detection mechanisms from their side and introduce additional fallback options ## **Conclusion** If you are still experiencing any unusual SMS delivery rate fluctuations or if you have any questions or concerns please contact our Support Team.