# Duo Phone Call Authentication Failure for US Based Carriers

- Provider: [Duo Security](https://down.guide/duo)
- Level: confirmed
- Impact: Degraded
- lasted 3h 15m
- started 2026-03-22 17:18 UTC
- us
- id: DWN-a34009667a
- Official page: https://stspg.io/gb8nrv3dcbml

## Updates from Duo Security
### 2026-03-22 17:18 UTC: investigating
We are currently investigating an issue causing VOIP authentication failures in all the deployments in the US region and are working to correct the issue as soon as possible. At this time please use alternative authentication methods such as Duo Mobile Push, or SMS passcodes.
A list of all other alternative authentication methods can be found here:
https://duo.com/docs/policy#authentication-methods
Please check back here or subscribe to updates for any changes.

### 2026-03-22 19:13 UTC: investigating
We are observing a recovery in voice call processing across the U.S. and are continuing to investigate the root cause of this impact.

### 2026-03-22 20:00 UTC: monitoring
We are now observing high rates of success of VoIP authentication. We will continue to monitor the situation.

### 2026-03-22 20:33 UTC: resolved
VoIP authentication has returned to normal operation with sustained success rates observed.

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