How to Fix Delta iOS Chinese Error 40021 & 40000 (October 2026 Update)

If a wall of Chinese text pops up when you try to launch Delta Executor on your iPhone, you’re in the right place. Error codes 40021 and 40000 have become the #1 headache for iOS users this year, but they’re almost always fixable without a computer science degree. This guide breaks down what each error actually means, what’s causing them, and the exact steps to get Delta back online.

What Are Delta iOS Chinese Errors 40021 and 40000? (Meaning Explained)

When Delta throws a Chinese error, it’s because the app’s integrity check failed before it could even open. Error 40021 typically translates to something like “无法验证应用完整性”, “Unable to verify app integrity.” In plain English, iOS or Delta’s own verification system decided the app isn’t genuine or its signing certificate is toast.

Error 40000 is a bit broader. It usually reads “连接服务器失败” or “Failed to connect to server,” meaning the app couldn’t phone home to Delta’s verification backend. That could be a network block, a VPN that’s messing with the request, or the server itself temporarily rejecting the check. Both errors leave you staring at a Chinese pop-up with nowhere to go, but the fixes are straightforward.

Why Do Chinese Errors 40021 & 40000 Appear on Delta Executor?

These errors trace back to Apple’s tight control over sideloaded apps. Delta isn’t on the App Store; it’s installed through AltStore, SideStore, or an enterprise certificate. When the certificate gets revoked, expires, or Apple simply blacklists it, the app’s signature becomes invalid, that’s error 40021. Check our expired certificate fix guide if you suspect this is the case.

Error 40000 is more often a connectivity gremlin. School or work Wi‑Fi networks, VPNs, or even Apple’s own iCloud Private Relay can block the verification server. Sometimes Delta’s own backend goes down briefly. If you’re running an older iOS version (below 15.0), the app’s verification protocol might simply not be supported anymore. There’s also a chance a botched installation left corrupted files that trigger the integrity fail.

How to Fix Delta iOS Chinese Error 40021 (Step‑by‑Step)

I’ve helped dozens of users through error 40021 on our Discord, and nine times out of ten it’s a certificate that needs refreshing. Here’s the sequence that works most consistently in 2026.

  1. Clear Delta’s cache and re‑verify the developer profile. Go to Settings > General > VPN & Device Management, find the Delta Executor profile, tap “Trust” again if it’s still there. If the profile is missing entirely, the certificate was revoked, head to our iOS untrusted developer guide to re‑establish trust.
  2. Refresh the installation through AltStore or SideStore. Connect your iPhone to the computer that runs AltStore, open AltServer, and hit “Refresh All.” This re‑signs Delta with a fresh certificate without erasing your scripts. Make sure your Apple ID hasn’t hit its app‑signing limit (3 apps per free account).
  3. Revoke and re‑sign the app completely. In AltStore, go to “View App IDs,” revoke the Delta certificate, then delete Delta from your iPhone. Reinstall Delta Executor for iOS fresh. Use a different Apple ID if the old one keeps getting flagged, a fresh throwaway account often sidesteps hidden revokes.

How to Fix Delta iOS Chinese Error 40000 (Step‑by‑Step)

Error 40000 is a network or compatibility problem, so we’ll focus on what’s between your iPhone and Delta’s servers.

  1. Check iOS version compatibility. Delta in 2026 officially supports iOS 15.0 through 18.x. Anything lower and you’ll likely see error 40000 every time. Update via Settings > General > Software Update if you can.
  2. Disable VPN, proxy, and iCloud Private Relay. These can route traffic through a region that Delta’s verification servers don’t like, or simply block the connection. Turn them all off temporarily, then relaunch Delta. If it works, you can try re‑enabling them one at a time to find the troublemaker. For persistent network issues, see our network error troubleshooting page.
  3. Reinstall Delta from scratch. Delete the app, remove any leftover configuration profiles from Settings, then grab a new copy from the iOS Delta download. During reinstallation, make sure your iPhone has a stable internet connection and is on a clean home network, not a public hotspot.

Quick Fixes Checklist – Delta iOS Error 40021 & 40000

Run through this list when you don’t have time to deep‑dive. Many users fix both errors with just a couple of these steps.

  • Restart your iPhone, it genuinely helps re‑trigger certificate checks.
  • Verify the developer profile is trusted under Settings > General > VPN & Device Management.
  • Make sure Airplane Mode is off and Wi‑Fi is connected to a stable home network.
  • Temporarily remove any VPN, ad‑blocking DNS, or proxy configuration.
  • Open AltStore or SideStore and refresh all apps to re‑sign certificates.
  • If the profile is missing, delete Delta and reinstall from a trusted source.
  • Disable iCloud Private Relay for a moment (Settings > [Your Name] > iCloud > Private Relay).
  • Check that your Apple ID isn’t at the 3‑app signing limit; revoke unused IDs in AltStore.

Advanced Troubleshooting When Basic Fixes Don’t Work

If you’ve followed everything above and the Chinese error still greets you, we need to reset the signing environment entirely. First, open AltStore or SideStore and revoke all existing certificates, not just Delta’s. Then sign out of the Apple ID you used for sideloading and sign in with a brand‑new account (a secondary iCloud account works fine for this). Reinstall Delta fresh, and most deep‑rooted signing errors will clear up.

Sometimes iOS itself is the culprit. Go to Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings. This won’t delete your data but will wipe saved Wi‑Fi passwords and VPN configurations, which can eliminate any weird network‑level blocks. Afterward, update iOS to the latest version Apple offers for your device, an outdated system daemon can interfere with app verification.

Still stuck? The Delta Executor team actively monitors these issues. Reach out through our contact page with a screenshot of the error and your device model; we’ll point you to the latest working workaround.

Frequently Asked Questions (FAQ)

Is Delta iOS Chinese error 40021 dangerous?

No. Error 40021 isn’t malware or a security threat, it’s just a verification failure. Your device is safe. However, using script executors can put your Roblox account at risk. Read our full disclaimer to understand the trade‑offs.

Can I fix error 40000 without a computer?

Yes, if you have AltStore or SideStore installed on your iPhone and it’s still signed. Refresh the apps on‑device to re‑validate Delta. If AltStore itself is expired, you’ll need a computer to re‑install the store and then Delta. A computer makes things faster, but it’s not always required.

Why does error 40021 show Chinese text?

The Delta Executor development team primarily communicates in Chinese, so error strings are hard‑coded in that language. It’s not a localization bug, it’s simply the default. The actual meaning is universal: the app failed its integrity check.

Does jailbreaking help fix these errors?

Technically a jailbreak can bypass Apple’s signing requirements, so errors 40021/40000 might not appear. But we strongly discourage jailbreaking. It voids your warranty, makes your device less secure, and often causes more stability issues than it solves. Delta is built to run without a jailbreak, and the sideloading fixes above keep your phone safe.