---
title: "Document Engine: 401 response"
canonical_url: "https://www.nutrient.io/guides/document-engine/troubleshooting/errors-and-warnings/401-response/"
md_url: "https://www.nutrient.io/guides/document-engine/troubleshooting/errors-and-warnings/401-response.md"
last_updated: "2026-06-08T13:19:33.871Z"
description: "Solutions for common issues and errors in Nutrient Document Engine SDK with debugging tips and workarounds."
---

# 401 Response

Make sure you’ve set the `Authorization` header to `Token token=<secret>`, where `<secret>` is the API authentication token you’ve set in your `docker-compose.yml` file with the `API_AUTH_TOKEN` environment variable.

The Server API should only be accessed from your backend servers and not by the clients. Giving the API authentication token to clients is a security concern. More information about how Document Engine is secured can be found in the [Nutrient security](https://www.nutrient.io/guides/document-engine/about/security.md) guide.
---

## Related pages

- [504 Response](/guides/document-engine/troubleshooting/errors-and-warnings/504-response.md)
- [Docker pull rate limit](/guides/document-engine/troubleshooting/errors-and-warnings/pull-rate-limit.md)
- [CORS errors](/guides/document-engine/troubleshooting/errors-and-warnings/cors.md)
- [RequestTimeTooSkewed](/guides/document-engine/troubleshooting/errors-and-warnings/request-time-too-skewed.md)
- [No ACTIVATION_KEY or LICENSE_KEY set](/guides/document-engine/troubleshooting/errors-and-warnings/no-activation_key.md)
- [503 service unavailable (overload)](/guides/document-engine/troubleshooting/errors-and-warnings/overload.md)