# X_CONFIG_INVALID

## Means

a configuration this process cannot boot on — env **or** `app.config.ts`

## Typical cause

a field failed its schema, a required field is missing, or two keys that each parse contradict each other (`selectMailDriver`, `selectPurgeDriver`), or a declaration whose guarantee this build cannot enforce (`defineAuth({ mfa: { required: true } })` — nothing reads it, so believing it would be a false security claim)

## Fix

`x doctor --json` and fix the named key; see [Configuration](/configuration)

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