Dev container unable to install (or lookup) extensions (503)

[pmalacho (Parker Malachowsky)]

Describe the Bug

When my dev container starts up, none of the extensions included in my configuration, and I see in the logs:

[3838 ms] [17:29:24] Error while installing extensions: Server returned 503
[3842 ms] [17:29:24] Failed: Server returned 503
    at Cc.N (file:///vscode/cursor-server/bin/linux-x64/031e7e0ff1e2eda9c1a0f5df67d44053b059c5d0/out/server-main.js:46:179176)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async Cc.J (file:///vscode/cursor-server/bin/linux-x64/031e7e0ff1e2eda9c1a0f5df67d44053b059c5d0/out/server-main.js:46:172526)
    at async Cc.D (file:///vscode/cursor-server/bin/linux-x64/031e7e0ff1e2eda9c1a0f5df67d44053b059c5d0/out/server-main.js:46:166981)
    at async Cc.getExtensions (file:///vscode/cursor-server/bin/linux-x64/031e7e0ff1e2eda9c1a0f5df67d44053b059c5d0/out/server-main.js:46:165853)
    at async Kc.j (file:///vscode/cursor-server/bin/linux-x64/031e7e0ff1e2eda9c1a0f5df67d44053b059c5d0/out/server-main.js:74:1261)
    at async Kc.g (file:///vscode/cursor-server/bin/linux-x64/031e7e0ff1e2eda9c1a0f5df67d44053b059c5d0/out/server-main.js:73:36906)
    at async Kc.installExtensions (file:///vscode/cursor-server/bin/linux-x64/031e7e0ff1e2eda9c1a0f5df67d44053b059c5d0/out/server-main.js:73:35555) {
  code: 'Failed'
}
[3844 ms] [17:29:24] Relaying the following extensions to install later: dbaeumer.vscode-eslint, ms-vscode.vscode-typescript-next, svelte.svelte-vscode, GitHub.copilot, ms-azuretools.vscode-docker, bradlc.vscode-tailwindcss

I also get a pop up of a 503 error when searching for extensions (photo attached).

Steps to Reproduce

1. Start / rebuild a devcontainer with the following configuration:

.devcontainer/devcontainer.json

{
  "name": "...",
  "dockerFile": "Dockerfile",
  "customizations": {
    "vscode": {
      "extensions": [
        "ms-vscode.vscode-typescript-next",
        "svelte.svelte-vscode",
        "GitHub.copilot",
        "ms-azuretools.vscode-docker",
        "bradlc.vscode-tailwindcss",
      ]
    }
  },
  "features": {
    "ghcr.io/devcontainers/features/node:1": {}
  }
}

.devcontainer/Dockerfile

# See here for image contents: https://github.com/microsoft/vscode-dev-containers/tree/v0.187.0/containers/typescript-node/.devcontainer/base.Dockerfile

# [Choice] Node.js version: 16, 18, 20
ARG VARIANT="20-buster"
FROM mcr.microsoft.com/vscode/devcontainers/typescript-node:0-${VARIANT}


# [Optional] Uncomment this section to install additional OS packages.
# RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
#     && apt-get -y install --no-install-recommends <your-package-list-here>

# [Optional] Uncomment if you want to install an additional version of node using nvm
# ARG EXTRA_NODE_VERSION=10
# RUN su node -c "source /usr/local/share/nvm/nvm.sh && nvm install ${EXTRA_NODE_VERSION}"

# To install more global node packages
RUN su node -c "npm install -g pnpm@9"

Observe that none of your desired extensions have installed.

Screenshots / Screen Recordings

Operating System

MacOS

Current Cursor Version (Menu → About Cursor → Copy)

Version: 1.2.1
VSCode Version: 1.99.3
Commit: 031e7e0ff1e2eda9c1a0f5df67d44053b059c5d0
Date: 2025-07-03T06:08:06.355Z (11 hrs ago)
Electron: 34.5.1
Chromium: 132.0.6834.210
Node.js: 20.19.0
V8: 13.2.152.41-electron.0
OS: Darwin x64 24.4.0

Does this stop you from using Cursor

Yes - Cursor is unusable

[ofek (Ofek Lev)]

We are also experiencing this, starting today.

[CK-iRonin.IT (CK)]

Same here and more… Devcontainers completely broken.

[ravirahman]

We are experiencing a degraded marketplace currently. We will update https://status.cursor.com/ with the incident status. We have traced down the issue and are working on fixing it.