DeepSeek Harness Web UI not connecting: gray send button and 404 errors

DeepSeek Harness Web UI not connecting has three typical symptoms: a send button that stays gray (no workspace selected), /api/commands/list returning 404 (command registration failed), and a blank plugin panel on remote access (plugin management is local-only). They map to three different root causes — fix them in this order: select a workspace → manage plugins locally → restart the web service and verify.

DeepSeek Harness Web UI not connecting: the three symptoms

The three symptoms are different and so are their root causes: a gray button is a state problem, a 404 is an API problem, and a blank panel is an access-method problem. One by one (source: dshbase troubleshooting):

1. Send button stays gray — the Web UI opens, the input box accepts text, but the send button is unclickable; this usually happens right after startup or when a new profile is created;
2. /api/commands/list returns 404 — the command menu is empty, and visiting the endpoint directly in the browser returns 404; this usually happens after installing a new plugin;
3. Blank remote plugin panel — opening the Web UI from a LAN IP or a tunnel shows a silently empty "Settings → Plugins" with no hint at all;
4. All three can be mistaken for "the Web UI is broken", but the fixes are completely different — match the symptom first.

Why the DeepSeek Harness Web UI fails: no workspace, local-only plugins, broken command API

Three root causes: the web profile has no workspace so sending is disabled; plugin management is bound to the local file system and unavailable remotely; and the command API returns 404 because plugin registration did not take effect. In detail:

1. No workspace selected: the web profile must have a workspace before it can send — without one, the Agent has no working directory and sending is disabled (source: dshbase troubleshooting);
2. Plugin management is local-only: opening the Web UI from another machine shows a silently blank plugin panel — plugin management is bound to the local file system, and dsh web listens on 127.0.0.1 by default (source: DeepSeek Harness README); a remote browser can chat, but plugin installs and removals must happen locally (source: dshbase troubleshooting);
3. Broken command API: /api/commands/list returning 404 means the plugin-manifest auto-discovery mechanism failed and commands were not registered (source: dshbase troubleshooting) — common when a plugin was installed without a restart, or the plugin never activated.

Fix DeepSeek Harness Web UI: select workspace, manage plugins locally, restart and verify

Route by symptom: a gray button means select a workspace, a blank panel means go back to the local machine, and a 404 means reinstall the plugin and restart the service. Step by step:

1. Select a workspace (fixes the gray send button) — find "Choose workspace" at the top of the Web UI, open it and pick a directory:
   • Click the "Choose workspace" button;
   • In the file picker, select a project directory (or create a new empty one);
   • The send button should become clickable and the input box ready.
2. Manage plugins locally (fixes the blank remote panel) — go back to the machine running dsh, open http://127.0.0.1:3080 in the browser, and install/uninstall/update plugins under "Settings → Plugins"; a remote browser is for viewing and chatting only, plugin operations must be local (source: dshbase troubleshooting).
3. Reinstall the plugin and restart the web service (fixes the commands/list 404) — reinstall the plugin under "Settings → Plugins", then restart the web service in the terminal:
   bash

   # Press Ctrl+C in the terminal running dsh, then run:
   dsh web
   

   Wait until the terminal prints http://127.0.0.1:3080, then refresh the browser.
4. Verify the endpoint — visit http://127.0.0.1:3080/api/commands/list:
   • A 200 with JSON data → the command menu is back;
   • Still 404 → check whether the plugin is activated (see "DSH plugin installed but not active"), and report the error if it persists (source: dshbase troubleshooting).
5. Rule out leftover instances — if it is still broken, check for port conflicts: lsof -i :3080 (macOS/Linux) or netstat -ano | findstr :3080 (Windows), kill the old process and restart; see "Fix port 3080 already in use".

How to verify a DeepSeek Harness Web UI fix: three endpoint checks and a real message

After the fix run three checks — the command endpoint returns 200, the service is listening, the workspace took effect — then close with a real chat message; only when all pass is the Web UI truly connected. In order:

1. Check the command endpoint — in the browser or the terminal:

   bash

   curl -i http://127.0.0.1:3080/api/commands/list
   

   An HTTP/1.1 200 with JSON data means the command menu is back; a persistent 404 means the plugin is not activated or not restarted — back to step 3 of the fix section.

2. Check the service is listening:

   bash

   lsof -i :3080
   

   A dsh process in LISTEN state means the service is healthy; no output or a PID conflict points to a leftover instance — back to step 5 of the fix section.

3. Check the workspace took effect — "Choose workspace" at the top of the Web UI now shows a directory, and the send button is clickable instead of gray.

4. Close with a real message — send a test message in a session; a normal send and reply means the Web UI is truly connected.

5. Remote scenario review (optional) — a blank "Settings → Plugins" over remote access is by design: confirm plugin management works on the local dsh machine, and that the remote browser can chat.

Notes: DeepSeek Harness Web UI — match the symptom first

1. For a gray send button, select a workspace first — do not rush to reinstall; this is the most commonly mis-fixed state problem.
2. A blank remote panel is by design, not a fault — manage plugins back on the local machine.
3. For a /api/commands/list 404, reinstall the plugin first, then restart the service; command registration follows plugin activation.
4. Back on the local machine, the most convenient way is Settings → Plugin Market (DSH Plugin Hub) — visual install/uninstall/update with clear failure reasons.
5. See install error troubleshooting for other DeepSeek Harness install errors.

Sources: dshbase troubleshooting, DeepSeek Harness apps/web, DeepSeek Harness README