Ciptex incident
Twilio - Voice Call Audio Quality Degradation between a Subset of Twilio Phone Numbers and T-Mobile in United States
Ciptex experienced a minor incident on May 12, 2026 affecting Twilio PSTN and Twilio Voice, North America, lasting 1d 20h. The incident has been resolved; the full update timeline is below.
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.