# Troubleshooting > Find the cause of a DS Server problem by its symptom: startup errors, 401 answers and token errors, Document Editor and Viewer connections, and limits on Linux. - **Product:** DS Server - **Section:** Documentation - **Kind:** Topic - **Path:** DS Server > Troubleshooting - **732 words** - **Web URL:** https://docs.textcontrol.com/ds-server/troubleshooting/ - **LLMs URL:** https://docs.textcontrol.com/ds-server/troubleshooting/llms.txt - **LLMs-Full URL:** https://docs.textcontrol.com/ds-server/troubleshooting/llms-full.txt --- When DS Server doesn't do what you expect, the message you see usually points to the cause: a process that ends at startup, a 401 or 400 response, an editor that shows a box instead of a document. Troubleshooting is organized by these symptoms. Each page quotes the messages of DS Server 5.0.2 as they appear on the console, in the log, in a response or in the browser, explains why they occur and lists the steps that fix them. ### Find the Right Page | If you see | Read | |---|---| | The server ends at startup, listens on another port or reports a missing .NET framework | [Installation](https://docs.textcontrol.com/ds-server/troubleshooting/installation/llms-full.txt) | | Every document request returns "DS Server is not registered." | [Installation](https://docs.textcontrol.com/ds-server/troubleshooting/installation/#every-document-request-says-ds-server-is-not-registered) | | A 401 response, a failed token request or a redirect URI error | [Authentication](https://docs.textcontrol.com/ds-server/troubleshooting/authentication/llms-full.txt) | | Requests work without any token | [Authentication](https://docs.textcontrol.com/ds-server/troubleshooting/authentication/#requests-work-without-a-token) | | The Document Editor can't connect, loses its connection or shows a license message | [Document Editor and Viewer](https://docs.textcontrol.com/ds-server/troubleshooting/editor-viewer/llms-full.txt) | | The Document Viewer doesn't load in an HTML page | [Document Editor and Viewer](https://docs.textcontrol.com/ds-server/troubleshooting/editor-viewer/#the-viewer-script-doesn-t-load) | | A format, bitmap rendering or a font behaves differently on Linux | [Linux](https://docs.textcontrol.com/ds-server/troubleshooting/linux/llms-full.txt) | ### Collect the Evidence First - **The log file.** DS Server writes almost nothing to the console. Its messages, including the address it listens on and every startup error, are in *logs/log\_YYYYMMDD.log*. See [Find Out Whether the Server Runs](https://docs.textcontrol.com/ds-server/troubleshooting/installation/#find-out-whether-the-server-runs). - **The response.** Token requests that fail return 400 with a JSON `error` and `error_description`. Refused requests return 401, and the `WWW-Authenticate` header tells a missing token from an invalid one. See [Requests Return 401 Unauthorized](https://docs.textcontrol.com/ds-server/troubleshooting/authentication/#requests-return-401-unauthorized). - **The browser console.** The Document Editor logs the address of its WebSocket connection and the errors of the token request and the license check. See [Find Out Where It Fails](https://docs.textcontrol.com/ds-server/troubleshooting/editor-viewer/#find-out-where-it-fails). - **The admin portal.** The **Licensing** page shows whether the server is registered, and the **Security Profiles** page whether OAuth is enabled. ### Where to Start 1. **A new installation doesn't work:** [Installation](https://docs.textcontrol.com/ds-server/troubleshooting/installation/llms-full.txt), then [Authentication](https://docs.textcontrol.com/ds-server/troubleshooting/authentication/llms-full.txt) once the server answers. 2. **The Document Editor or Document Viewer stays empty:** [Document Editor and Viewer](https://docs.textcontrol.com/ds-server/troubleshooting/editor-viewer/llms-full.txt), which links to the token problems on [Authentication](https://docs.textcontrol.com/ds-server/troubleshooting/authentication/llms-full.txt). 3. **An installation moved from Windows to Linux:** [Linux](https://docs.textcontrol.com/ds-server/troubleshooting/linux/llms-full.txt). If a problem started after an update, read the Upgrading section of the version in [What's New](https://docs.textcontrol.com/ds-server/whats-new/llms-full.txt). For the requests and responses of each endpoint, see the [Web API](https://docs.textcontrol.com/ds-server/reference/web-api/llms-full.txt) reference, and for the status codes of document requests, [Errors and Status Codes](https://docs.textcontrol.com/ds-server/document-processing/errors/llms-full.txt). --- ## In This Section - [Authentication](https://docs.textcontrol.com/ds-server/troubleshooting/authentication/llms-full.txt): Fix 401 Unauthorized and failed token requests: OAuth off, no authorization header, grant type not allowed, invalid secret, redirect URI, lost admin password. - [Document Editor and Viewer](https://docs.textcontrol.com/ds-server/troubleshooting/editor-viewer/llms-full.txt): Fix a Document Editor or Viewer that stays empty: not registered, WebSocket fails or drops, TXTextControl.init errors, a viewer script 401, React with Vite. - [Installation](https://docs.textcontrol.com/ds-server/troubleshooting/installation/llms-full.txt): Fix a DS Server that ends at startup with an HTTPS or port error, ignores ASPNETCORE_URLS, misses a runtime, isn't registered or rejects a serial number. - [Linux](https://docs.textcontrol.com/ds-server/troubleshooting/linux/llms-full.txt): Fix DS Server problems on Linux: no DOC, RTF or TX support, SVG-only page images, replaced fonts, ARM64 and Alpine, and a log written to another folder. --- ## Nearby - **Previous:** [Custom Signing Endpoints](https://docs.textcontrol.com/ds-server/plugins/signing/llms-full.txt) - **Next:** [Installation](https://docs.textcontrol.com/ds-server/troubleshooting/installation/llms-full.txt)