failed to ensure mise is installed / failed to download and install from Github

Question

**Subject: Railpack deployment consistently fails downloading mise from GitHub (503/504)**

Hello Railway team,

I'm unable to deploy my Next.js application. It builds successfully on localhost, and previous Railway deployments worked correctly.

However, every new deployment now fails during Railpack's environment preparation, before my application build even starts.

The relevant errors are:

```
using build driver railpack-v0.43.0
failed to ensure mise is installed
failed to download and install
https://github.com/jdx/mise/releases/download/v2026.10.14/mise-v2026.10.14-linux-x64-musl.tar.gz
503 Service Unavailable
504 Gateway Timeout
railpack process exited with an error
```

I've retried deployment multiple times, with the same result.

Could you investigate why the Railpack builder cannot download mise and advise how to get deployments working again?

Thank you!