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If you encounter a “WebAssembly not found” error when using ID Check on iOS devices, follow these troubleshooting steps in order.

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Understanding the Problem

This error occurs when WebAssembly functionality is blocked by iOS security settings or browser environment. In particular, when Lockdown Mode is enabled, WebAssembly execution is forcibly blocked in Safari, causing a ReferenceError: Can't find variable: WebAssembly error. Check each method below one by one.

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Solutions

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1. Check and Disable Lockdown Mode

If Lockdown Mode is enabled on iOS 16 or later, WebAssembly will be blocked. Lockdown Mode is hidden at the bottom of the menu due to its high security level.
1

Open Settings app

Open the Settings app on your iPhone.
2

Navigate to Privacy & Security

Select the Privacy & Security menu.
3

Scroll to the bottom

Scroll to the very bottom (all the way down) of the screen.
4

Check Lockdown Mode

Find the Lockdown Mode option at the bottom of the Security section and check its current status.
5

Disable Lockdown Mode

If Lockdown Mode is set to On, tap the toggle to change it to Off.
If the Lockdown Mode menu is not visible:
  • Check iOS version: Lockdown Mode is only supported on iOS 16 or later. If you’re using iOS 15 or earlier, this menu will not appear. (You can check your version in Settings > General > About)
  • Device restrictions: In rare cases, if your device is managed by a company or school with an MDM (Mobile Device Management) profile installed, certain security settings may be restricted and the menu may not be visible.
If you need to keep Lockdown Mode enabled for security reasons, you can exclude the ID Check site from Lockdown Mode in Safari’s website settings. Open the site in Safari, tap the aA icon next to the address bar, then select Website Settings and choose to exclude it from Lockdown Mode.
Lockdown Mode is a security-enhancing feature. Be aware of security risks after disabling it.
iOS Settings showing Lockdown Mode in Privacy & Security section

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2. Open in Safari Browser Directly

Issues may occur when using in-app browsers or apps added to the home screen.
1

Open Safari browser

Launch the Safari app directly on your iPhone.
2

Enter URL in address bar

Enter the full address of the ID Check page in Safari’s address bar.
3

Retry the page

Refresh the page or start over from the beginning.
WebAssembly may not work in browsers opened from within apps like KakaoTalk, Facebook, or Instagram. Try opening the page directly in the Safari app.

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3. Check Safari Experimental Features

WebAssembly may be disabled in Safari’s experimental features settings.
1

Open Settings app

Open the Settings app on your iPhone.
2

Navigate to Safari

Select the Safari menu.
3

Select Advanced

Select the Advanced menu at the bottom of the screen.
4

Check Experimental Features

Select the Experimental Features menu.
5

Verify WebAssembly

Find the WebAssembly item in the list and verify it is set to On.
WebAssembly is enabled by default in most recent iOS versions. However, if it was manually changed previously, you may need to verify this setting.

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4. Check iOS Version

WebAssembly is only supported on iOS 11 or later.
1

Open Settings app

Open the Settings app on your iPhone.
2

Select General

Select the General menu.
3

Check About

Select the About menu.
4

Check Software Version

Check your current iOS version in the Software Version item.
If you’re using iOS 10 or earlier, you need to update iOS. Go to Settings > General > Software Update to proceed with the update.

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5. Clear Cache and Data

The issue may be caused by browser cache or stored data.
1

Open Safari settings

Go to Settings > Safari.
2

Clear History and Website Data

Select Clear History and Website Data.
3

Confirm

Select Clear in the confirmation message.
4

Retry the page

Open Safari again and reload the ID Check page.

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If the Problem Persists

If you’ve tried all the methods above and the problem still persists:
  1. Restart device: Turn off your iPhone completely and turn it back on.
  2. Restart Safari app: Completely close the Safari app and launch it again.
  3. Check network: Verify you’re using a stable Wi-Fi or cellular connection.
In most cases, disabling Lockdown Mode or opening the page directly in Safari browser resolves the issue. If the problem persists, please contact customer support.