Duo Security: All Deployments: Duo Phone Call and SMS Delivery Failure

What to do

Check whether you use Duo Security Phone Call Delivery, Phone Call Delivery, Phone Call Delivery, Phone Call Delivery and 154 more. 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 2h 38m it lasted.
Anything that failed between 2025-10-20 08:28 UTC and 2025-10-20 11:06 UTC may need a replay.
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https://down.guide/feed?provider=duo works in Slack (/feed subscribe), Discord feed bots and any RSS reader.

investigatingOct 20, 2025, 8:29 AM UTC
We are currently investigating an issue causing phone call and SMS delivery authentication failures on all of our deployments and are working to correct the issue as soon as possible. Please check back here or subscribe to updates for any changes.
provider
identifiedOct 20, 2025, 8:52 AM UTC
We've identified the cause of degraded Phone Authentication and SMS delivery failures. Our providers have acknowledged an upstream issue and are working on a resolution. This may affect users relying on phone calls or SMS for authentication across all deployments and we suggest using alternate means of MFA such as Duo Push if possible. Our team is working on mitigation steps and will continue to provide updates as progress is made.
provider
resolvedOct 20, 2025, 11:06 AM UTC
The issue affecting phone-based authentication and SMS delivery has now been resolved. System performance has remained stable, and all services are operating as expected across deployments. We will continue to monitor for any anomalies, but no further impact is anticipated at this time.
provider

Reports count in aggregate; nothing about you is shown.

None so far.

Something wrong on this page? Report an error or send us a note. Every fix is listed here.

Is Duo Security still down?

No, this incident was resolved 2025-10-20 11:06 UTC. For Duo Security's live state, see https://down.guide/duo.

How long did it last?

2h 38m, from 2025-10-20 08:28 UTC to 2025-10-20 11:06 UTC, by the times Duo Security posted.

What was affected?

Duo Security named Phone Call Delivery, Phone Call Delivery, Phone Call Delivery, Phone Call Delivery and 154 more.

What caused it?

Duo Security hasn't published a root cause. If it does, it shows here.

Where does this come from?

Duo Security's official status page, https://status.duo.com, quoted verbatim. down.guide's own probes, reports and social counts are labeled as ours.