Cannot run `codesandbox-client` and `dependency-packager` locally together

🐛 bug report

Preflight Checklist

• I have read the Contributing Guidelines for this project.
• I agree to follow the Code of Conduct that this project
  adheres to.
• I have searched the issue tracker for an issue that matches the one I want
  to file, without success.

Description of the problem

I want to run codesandbox-client and dependency-packager locally together. Here is my steps:

1. yarn run build and yarn run dev under dependency-packager project
2. Replace bucket url by http://localhost:4545 at this line
3. yarn run start under codesandbox-client project.
4. When I create a React Application on http://localhost:3000. The terminal of dependency-packager report the error:
   

How has this issue affected you? What are you trying to accomplish?

To Reproduce

Link to sandbox: None

Your Environment

Reproduce the reported setup by building and running dependency-packager, changing the bucket URL in packages/sandpack-core/src/npm/preloaded/fetch-dependencies.ts at line 26, and starting codesandbox-client. Begin with the dependency-packager terminal error shown in the report. Done means both projects run together and creating a React application no longer produces that error.