# Duo Phone Call Authentication Failure for US Based Carriers

- Provider: [Duo Security](https://down.guide/providers/duo)
- Confidence: Confirmed
- Impact: Operational
- lasted 4h 10m
- started 2026-03-22 22:13 UTC
- us
- id: DWN-8ec300a3d2
- Official page: https://stspg.io/43mz410cgng5

## Updates from Duo Security
### 2026-03-22 22:13 UTC: investigating
We are currently observing a recurrence of the issue causing VOIP authentication failures in all deployments in the US region. We are working to correct the issue as soon as possible. While we work to resolve this, please use alternative authentication methods such as Duo Mobile Push, SMS passcodes etc.
A full list of available authentication methods can be found here:
https://duo.com/docs/policy#authentication-methods

### 2026-03-23 00:01 UTC: monitoring
We are now observing high rates of success of VoIP authentication. The issue appears to be resolved but we will continue to monitor the situation.

### 2026-03-23 02:23 UTC: resolved
VoIP authentication has returned to normal operation with sustained success rates observed.

From the builder: does your app depend on Duo Security? [Sazabi](https://www.sazabi.com/?utm_source=down-guide&utm_medium=markdown&utm_content=duo) detects problems in your own logs without hand-written monitors, and you can ask it in plain language which errors mention Duo Security.

---
down.guide reads providers' official status pages every minute and adds its own evidence, always labeled. Free, no account. Agents: MCP at https://down.guide/mcp, REST at https://down.guide/api/v1, feeds at https://down.guide/feed. Built by [Sazabi](https://www.sazabi.com/?utm_source=down-guide&utm_medium=markdown&utm_content=DWN-8ec300a3d2), AI-native observability and security: automatic issue detection, plain-language log search and live dashboards.