CDE Troubleshooting

This page covers common issues with the SecDim Cloud Development Environment (CDE).

Session Limits

  • Idle timeout: CDE sessions are automatically deleted after 10 minutes of inactivity. Save and push your work regularly.

  • Maximum session: CDE sessions have a maximum duration of 2 hours. After 2 hours the session will end regardless of activity.

If your session is deleted or expires, you can start a new one by clicking Open in CDE again on the challenge page. Your previously pushed commits are preserved on the server.

Browser Requirements

The CDE runs VS Code in the browser (Visual Studio Code for the Web). It requires a modern browser that supports this technology.

Supported browsers:

  • Google Chrome (recommended)

  • Microsoft Edge

  • Mozilla Firefox

  • Safari (recent versions)

Requirements:

  • JavaScript must be enabled

  • WebSocket connections must not be blocked (see Corporate Proxy or VPN Issues below)

  • A minimum viewport width of 1024px is recommended — the CDE is not optimised for mobile devices or small screens

  • Third-party cookies may need to be allowed for *.secdim.net

CDE Not Loading or Stuck at Loading

If the CDE gets stuck during loading or the sandbox percentage does not reach 100%:

  1. Click the delete icon on the CDE to remove the current session

  2. Click Open in CDE again to start a fresh session

  3. If the problem persists, try a different browser or disable browser extensions that may interfere (ad blockers, privacy extensions)

Corporate Proxy or VPN Issues

Corporate proxies and VPNs that block WebSocket connections will prevent the CDE from loading or cause it to disconnect.

Symptoms:

  • CDE loads but the editor is blank or unresponsive

  • Terminal does not connect

  • Frequent disconnections during a session

Solutions:

  • Ask your network administrator to allowlist *.secdim.net for WebSocket connections (ports 443)

  • If your proxy performs TLS inspection, it may need to bypass *.secdim.net

  • Try connecting outside the VPN/proxy to confirm the issue is network-related

See Network Allowlist for the full list of domains to allowlist.

Resetting Git History

If your repository is in a bad state (merge conflicts, accidental file deletions, broken commits), you can reset your git history at any time using:

make reset

This resets the repository to its original state. Any uncommitted changes and local commit history will be lost.

Using Dr. SecDim in the CDE

Dr. SecDim is available in the CDE via the S icon in the left sidebar.

When Dr. SecDim is reasoning or applying code changes:

  • Do not interact with the editor UI until the operation completes

  • Close any pop-up dialogs that appear during the process

  • Wait for Dr. SecDim to finish before making further edits or running commands

Interrupting Dr. SecDim during code application may result in partial or broken changes. If this happens, you can undo with Ctrl/Cmd + Z or use make reset to restore the original state.

Common Issues

Issue Solution

CDE deleted unexpectedly

Session timed out after 10 minutes of inactivity. Click Open in CDE to start a new session.

"Open in CDE" button not appearing

Ensure you have clicked Play to start the challenge first. The CDE button appears only after a challenge is started.

Terminal not opening

Right-click in the file explorer area and select Open Integrated Terminal. Alternatively, use the keyboard shortcut Ctrl/Cmd + ` `.

Cannot access the running app in browser

Check the Ports tab in the terminal panel. Click the globe icon to open the app in a new browser tab.

Extensions or settings not saving

CDE sessions are ephemeral. Installed extensions and custom settings are not preserved between sessions.

Screen too small to use the editor

The CDE requires a minimum viewport width of approximately 1024px. Use a desktop or laptop browser.

Still Need Help?

If your issue is not listed here: