# GitLab: GitLab Duo Chat (classic) returning errors

- Impact (vendor’s label): major
- Status: resolved
- Started: 2025-09-04 23:33 UTC · Resolved: 2025-09-05 00:33 UTC · Duration: 1.0 h
- Updates: 3 · Affected components: GitLab Duo
- [Vendor status page: https://status.gitlab.com/pages/incident/5b36dc6502d06804c08349f7/68ba21d8d7b04805114d9eb0](https://status.gitlab.com/pages/incident/5b36dc6502d06804c08349f7/68ba21d8d7b04805114d9eb0)
- [Company: GitLab](https://rewindex.com/company/gitlab.md)

## Timeline of updates

- **investigating** 2025-09-04 23:33 UTC: Our team is currently investigating an issue with Duo Chat (classic). Users may experience A1004 errors. Duo Chat (Agentic) is working normally
- **investigating** 2025-09-05 00:07 UTC: All messages to Duo Chat classic are currently receiving A1004 errors. Duo Chat (Agentic) is working normally. Our team is currently investigating. For more information, see https://gitlab.com/gitlab-com/gl-infra/production/-/issues/20483
- **resolved** 2025-09-05 00:33 UTC: A recent change has been reverted and confirmed as the cause. Duo chat (Classic) is now working. For details, see https://gitlab.com/gitlab-com/gl-infra/production/-/issues/20483

## Rewindex changes for this incident

- 2025-09-04 23:33 UTC: [Major incident: GitLab Duo Chat (classic) returning errors](https://rewindex.com/change/i2468e462d22185.md)


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Canonical: https://rewindex.com/company/gitlab/incidents/68ba21d8d7b04805114d9eb0 · Markdown: https://rewindex.com/company/gitlab/incidents/68ba21d8d7b04805114d9eb0.md · JSON: https://rewindex.com/api/v1/companies/gitlab/incidents/68ba21d8d7b04805114d9eb0 · Generated 2026-10-18T09:36:57.208Z