Ciptex incident
Twilio - Voice Call Audio Quality Degradation between a Subset of Twilio Phone Numbers and T-Mobile in United States
Resolved after 1 day 20 hours, affecting Twilio PSTN and Twilio Voice, North America, on May 12, 2026.
Following comprehensive monitoring, we can confirm that the incident has been fully resolved and all services have returned to normal operation.
Affected components
Update timeline
- investigating May 11, 2026, 04:05 PM UTC
We have detected potential service disruption through our monitoring systems and are actively investigating. A detailed assessment of the impact and affected services will be provided within the next 30 minutes.
- identified May 11, 2026, 06:14 PM UTC
Twilio customers may be experiencing voice call audio quality degradation between a subset of Twilio Phone Numbers and T-Mobile network subscribers in the United States. The Twilio team has identified the cause, and is working to resolve the issue. We will provide another update in 2 hours or as soon as more information becomes available.
- identified May 11, 2026, 08:01 PM UTC
Twilio customers may be experiencing voice call audio quality degradation between a subset of Twilio Phone Numbers and T-Mobile network subscribers in the United States. The Twilio engineering team has identified the cause, and is working to resolve the issue. We will provide another update in 4 hours or as soon as more information becomes available.
- monitoring May 12, 2026, 05:55 AM UTC
Twilio has observed a recovery in voice calls between a subset of Twilio Phone Numbers and T-Mobile network subscribers in the United States and are monitoring service stability. We will provide another update in 10 hours or as soon as more information becomes available.
- monitoring May 12, 2026, 09:36 AM UTC
Twilio has observed a recovery in voice calls between a subset of Twilio Phone Numbers and T-Mobile network subscribers in the United States and are monitoring service stability. We will provide another update in 4 hours or as soon as more information becomes available.
- monitoring May 12, 2026, 02:40 PM UTC
Twilio has observed a recovery in voice calls between a subset of Twilio Phone Numbers and T-Mobile network subscribers in the United States and are monitoring service stability. We will provide another update in 16 hours or as soon as more information becomes available.
- monitoring May 12, 2026, 06:15 PM UTC
Twilio has observed a recovery in voice calls between a subset of Twilio Phone Numbers and T-Mobile network subscribers in the United States and are monitoring service stability. We will provide another update in 4 hours or as soon as more information becomes available.
- monitoring May 13, 2026, 09:42 AM UTC
Twilio has observed a recovery in voice calls between a subset of Twilio Phone Numbers and T-Mobile network subscribers in the United States and are monitoring service stability. We will provide another update in 16 hours or as soon as more information becomes available.
- resolved May 13, 2026, 09:12 PM UTC
Following comprehensive monitoring, we can confirm that the incident has been fully resolved and all services have returned to normal operation.
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