Guideline 2.1: app completeness

The React Native failure modes

• Works in Debug, white screen in Release. The classic RN rejection. A reviewer opens a production build and gets a blank view. Causes cluster around bundling and asset resolution differing between configurations, and around code that only runs when a Metro dev server is reachable.
• Depends on a dev server that isn't there. Anything that assumes localhost fails on the reviewer's device.
• Environment variables absent in the release build. An API base URL that resolves to undefined produces an app that launches and does nothing.
• Expired or rate-limited demo credentials. The account worked when you filed and does not work when reviewed.
• Demo account behind a phone-SMS second factor. The reviewer cannot receive the code.

The check that prevents most of these

Install the exact build you are submitting on a device that has never run your project, on a network that cannot reach your dev machine, signed in with the demo credentials you put in App Store Connect. Most 2.1 rejections are a build that was never opened that way before it was submitted.

Related metadata rules in 2.3

Section 2.3 covers accurate metadata, and several sub-rules produce rejections that look unrelated to code:

• 2.3.1 — no hidden or undocumented features; don't ship anything that behaves differently for reviewers
• 2.3.3 — screenshots must show the app in use, not aspirational marketing imagery
• 2.3.10 — don't reference other mobile platforms in your metadata
• 2.3.12 — "What's New" must describe significant changes; generic text is acceptable only for bug fixes, security and performance