SMS Delivery — Encoding Issues on Outbound Messages to T-Mobile

What to do

• Check whether you use Telnyx NORAM. Check your stack

  Paste a package.json, lockfile, Terraform or a list of domains at down.guide/stack to see every provider you depend on.

• Confirm your retries, queues and scheduled jobs caught up after the 2d 18h it lasted.

  Anything that failed between 2026-09-15 21:57 UTC and 2026-09-18 16:26 UTC may need a replay.

• Subscribe to Telnyx's feed to hear about the next one first. RSS feed

  https://down.guide/feed?provider=telnyx works in Slack (/feed subscribe), Discord feed bots and any RSS reader.

Updates from Telnyx 3

1. investigatingSep 15, 2026, 9:57 PM UTC

   We are currently investigating reports of encoding issues affecting a subset of outbound SMS messages to T-Mobile. End users may be receiving messages with garbled or unreadable text. We are actively investigating with our downstream partner and will provide an update as soon as we have more information.

   provider

2. monitoringSep 16, 2026, 9:57 PM UTC

   Our downstream partner has deployed a fix for garbled message bodies on 10DLC SMS to T-Mobile destinations. The issue impacted 10DLC senders assigned to 501(c)(3) tax-exempt campaigns predominantly. Test messages to T-Mobile destinations are now delivering intact.

   provider

3. resolvedSep 18, 2026, 4:26 PM UTC

   Our downstream partner's fix for garbled message bodies on 10DLC SMS to T-Mobile destinations has been confirmed. Impact was limited to 10DLC senders assigned to 501(c)(3) tax-exempt campaigns. Both test and live traffic to T-Mobile destinations are delivering intact. An RCA will follow.

   provider

Corrections

None so far.

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