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