Resolved after 16 hours 15 minutes, affecting SMS Messaging (SMPP) and MMS Messaging (MM4) and 1 more, on September 10, 2026.
Between 23:00 UTC on September 8th and 15:00 UTC on September 11th, Bandwidth Messaging services experienced intermittent SMS/MMS delivery failures to AT&T destinations. Bandwidth has concluded its investigation of this issue and details can be found in the following Incident Report: [https://www.bandwidth.com/support/en/articles/17229559-20260909-messaging-at-t-4740-error-codes-to-at-t-destinations-nnid-mismatch](https://www.bandwidth.com/support/en/articles/17229559-20260909-messaging-at-t-4740-error-codes-to-at-t-destinations-nnid-mismatch). We are grateful you have entrusted Bandwidth as your communication partner and we are sorry if this issue resulted in any disruption to your services.
Affected components
Update timeline
- identified Sep 10, 2026, 06:04 PM UTC
Bandwidth teams have identified an off-network incident resulting in intermittent messages delivery failures to AT&T destinations. These failures result in a 4740 code. Teams are working with AT&T to restore expected delivery of messages.
- identified Sep 10, 2026, 11:24 PM UTC
Band with teams continue to partner with the impacted industry provider.
- identified Sep 11, 2026, 01:17 PM UTC
Bandwidth teams continue to partner with the impacted industry provider. Updates will be provided as they become available.
- resolved Sep 11, 2026, 06:20 PM UTC
This incident has been resolved.
- postmortem Sep 29, 2026, 12:14 PM UTC
Between 23:00 UTC on September 8th and 15:00 UTC on September 11th, Bandwidth Messaging services experienced intermittent SMS/MMS delivery failures to AT&T destinations. Bandwidth has concluded its investigation of this issue and details can be found in the following Incident Report: [https://www.bandwidth.com/support/en/articles/17229559-20260909-messaging-at-t-4740-error-codes-to-at-t-destinations-nnid-mismatch](https://www.bandwidth.com/support/en/articles/17229559-20260909-messaging-at-t-4740-error-codes-to-at-t-destinations-nnid-mismatch). We are grateful you have entrusted Bandwidth as your communication partner and we are sorry if this issue resulted in any disruption to your services.
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