Fix Vega Studio Build Issues

This page helps you resolve common issues when building and running apps with Vega Studio in VS Code.If you don't find a solution to your specific problem here, post an issue in Developer Forum for additional support.

Port forwarding fails with "operation unsuccessful" error

Cause: This error occurs when the simulator isn't running.

Solution:

1. Go to Kepler Studio panel > Devices.
2. If it shows VirtualDevice:Tv (Not running), go to Projects section and click the "play" button next to your project name.

Error loading webview in VS Code

While using VS Code, your screen might display the following message:

Copy code Copied to clipboard.

Error loading webview

Cause: This error happens when multiple instances of VS Code are open.

Solution: At the command prompt, run force quit all to quit all instances and restart VS Code.

React Native Tools extension fails to activate when creating new project

When creating a new project, you might receive this error message:

Copy code Copied to clipboard.

[Error] Failed to activate the React Native Tools extension (error code 702)

Cause: VS Code workspace configuration issues prevent the React Native Tools extension from loading properly.

Solution: Open your project as a workspace in the VS Code toolbar (File > Open Workspace from File) and save it as a new workspace.

React Native Packager is already running when trying to launch app

When trying to launch your app, you might see this error message:

Copy code Copied to clipboard.

Failed to execute command. React Native Packager is already running

Cause: This issue happens when you have a multi-project workspace and an app is currently running.

Solution: Stop the packager before launching another app. In the VS Code command palette, enter React Native: Stop Packager.

React Native Tools packager becomes unresponsive after selecting wrong project

When running multiple projects and accidentally selecting the wrong project name in the RN packager, the React Native: Stop Packager command becomes disabled.

Cause: The React Native Tools extension loses track of the active packager process when the wrong project is selected.

Solution: Reload the VS Code window using Command Palette: Developer: Reload Window.

1. Press Ctrl+Shift+P (Linux) or Cmd+Shift+P (Mac) to open Command Palette.
2. Type "Developer: Reload Window".
3. Select the command to reload VS Code.
4. Restart your project's packager.

No project templates appear when selecting a template

Cause: Environment variables from the Vega SDK aren't properly loaded in the current VS Code session.

Solution: Source the environment file from the Vega SDK installed directory. At the command prompt, open VS Code using code.

Build or launch fails due to port conflicts

Cause: Another process is using the required port.

Solution: Choose a different port to resolve the port conflict.

Fast Refresh feature doesn't update app when making code changes

Cause: Port forwarding connection issues prevent Fast Refresh from communicating with the device.

Solution: Reset your reverse port forwarding connection and relaunch your app:

1. Check the current list:

   Copy code Copied to clipboard.

   kepler exec vda reverse —list
   

2. Remove all list:

   Copy code Copied to clipboard.

   kepler exec vda reverse —remove-all
   

3. Relaunch your app.

Line-by-line-debugging isn’t working

Cause: Developer mode may not be properly configured or the debug host configuration is missing.

Solution: Verify developer mode and check shared_preferences.json to resolve the issue. See Configure Developer Mode on Fire TV Stick

To enable line-by-line debugging on the custom port, add the following configuration in shared_preferences.json file:

Copy code Copied to clipboard.

{
"debug_http_host": "localhost:<PORT>"
}

Make sure to replace <PORT> with the actual port number you’re using.

Related topics

• Build an App with Vega Studio

Last updated: Oct 08, 2025