# X_ENVIRONMENT_INVALID

## Means

`ULTIMATE_ENV` is not a known environment

## Typical cause

a spelling the framework does not use (`prod`, `dev`, `preview`). `NODE_ENV` is only a fallback and is never policed — CI images legitimately set it to anything

## Fix

`export ULTIMATE_ENV=production` — one of `development`, `test`, `staging`, `production`

[Config and environment](/error-codes#config-and-environment)