hs project migrate fails with internal server error — local dev proxy broken

Develop, Build & Integrate APIs & Integrations
1

I’m completely stuck and hoping someone has encountered this before.

Background

We have a public app project on platform version 2025.1 that was working fine until recently. The local.json proxy (routing hubspot.fetch() calls to our local backend during development) stopped working after a CLI update. hubspot.fetch() requests now bypass the local proxy and hit the internet directly, returning 404.

The CLI logs “Proxy config discovered, enabling local proxy mode” on startup, but requests are never routed through the proxy. Additionally, on exit we consistently see:

[ERROR] Failed to cleanup local dev server: The request failed.
✖ Failed to cleanup before exiting

Migration attempts

To fix this, we tried migrating to a newer platform version using hs project migrate. Every attempt fails with:

“An internal error occurred during this migration. No changes were made to your project or app. Please try the migration again.”

No component-level errors are returned. We’ve tried this across multiple CLI versions — 7.3.0, 7.4.8, 7.11.3, 8.3.0, and 8.4.0 (the currently recommended version per the docs).

One earlier attempt surfaced a different error: APP_FUNCTION: Migration is not supported from source platform version 2026.03. Only migrations from 2025.1 are currently supported. This is unexpected since our project is on 2025.1. We suspect that a separate test project sharing the same app ID may have partially migrated the app’s server-side state, leaving it corrupted.

What we’ve tried

  • Multiple CLI versions (v7 and v8)
  • hs project install-deps and clean npm install
  • Re-authenticating with fresh personal access keys
  • Resolving duplicate component UIDs when prompted
  • Renaming local.json to .bak to disable the proxy
  • Verifying allowedUrls includes the proxied domain
  • Confirming the local backend responds correctly to direct requests

None of this has worked. The local dev proxy doesn’t register on the server, and the migration tool consistently hits an internal server error.

Question

Has anyone else run into this? Is there a way to reset an app’s server-side state without going through support? Or is this definitively something only HubSpot support can fix?

Any guidance appreciated — this is blocking all local development.

2

Hey @sparkgrid,

Welcome to the Community!

I couldn’t find much on this error here, but I believe a good way to debug this is to try running the same command with the --debug flag

Could you confirm if running your service on another port resolves this issue?
In the meantime, I’d like to tag in some of our Top Contributors to see if they have any experience seeing this behavior!

@Anton, @SteveHTM, @zach_threadint -- Do you have any suggestions for @sparkgrid on this?
Thanks in advance!

Best,

Sam, Community Manager

3

Hi @sparkgrid,

A few things that helped us troubleshoot it:

  • Update the HubSpot CLI
    Older versions of the CLI can sometimes cause migration or proxy issues, so it’s worth updating to the latest version before retrying.
  • Re-authenticate your account
    Logging out and back in helped reset the session in our case before re-running the migration.
  • Double-check the project root and structure
    Make sure you’re running the command from the correct directory and that your hsproject.json file and related configs are valid.
  • Test local dev separately
    Try running the local dev command on its own. If the proxy fails as well, it can sometimes point to port conflicts or environment issues rather than the migration itself.

If none of that helps, and you’re still getting an internal server error, it may be worth raising it with HubSpot support or checking if others are seeing similar behavior, as sometimes these errors can be platform-side.

Hope this helps, curious to hear what you find.

(Taken help from ai)