X_ENV_MISSING
Means
required environment variables are missing or invalid
Typical cause
a key absent at boot; validation runs before the server listens
Fix
x env check --json, then set the keys it names. There is no --fix: x env declares check and example and no flags of its own (packages/cli/src/cmd-env.ts), so the flagged form dies at the parser with X_CLI_BAD_FLAG