NextDeveloperv0.5.0-beta.0
  1. Help
  2. Troubleshooting
  3. Common issues

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Troubleshooting

Common issues

Solutions for code that won't run, sign-in problems, and missing progress.

Last updated 2026-07-18

Here are quick fixes for the most common problems learners run into.

Code will not run

  1. Check the console for an error message and the line number.
  2. Make sure you did not delete starter code that the tests rely on.
  3. Verify that your function names and variable names match the instructions.
  4. Try pressing Run again. The execution environment occasionally times out.

The preview panel is blank

  • Confirm the output is directed to the preview, not the console.
  • Make sure your HTML file is named index.html if the lesson expects it.
  • Check the browser console for JavaScript errors.

I cannot sign in

  • Check your email and password.
  • If you use magic links or SSO, make sure the link has not expired.
  • Try a different browser or clear cookies for nextdeveloper.com.

My progress disappeared

Progress is tied to your account. If you used the site without signing in, make sure you sign in with the same email. Free users keep progress across sessions after signing up.

Still stuck?

Ask in the Community Forum or email hello@nextdeveloper.com.

Related articles

Code editor overview

How the in-browser editor works and what you can do with it.

Account & settings overview

How to update your profile, change paths, manage notifications, and sign out.

Still have questions?

Our team is happy to help. Send us an email or visit the community forum.

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On this page

  • Code will not run
  • The preview panel is blank
  • I cannot sign in
  • My progress disappeared
  • Still stuck?