The tunnel connection failed while the system tried to connect to the device. (XCode and iPhone)

Question

The tunnel connection failed while the system tried to connect to the device. (XCode and iPhone)

Hello,

I’m new to macOS after many years on iPhone, and I’m trying to run a simple app on my iPhone directly from Xcode. The app builds fine in the simulator, but deploying to a real device fails with this error:

The tunnel connection failed while the system tried to connect to the device.
Domain: com.apple.dt.CoreDeviceError
Code: 4
Failure Reason: The tunnel connection failed while the system tried to connect to the device.
User Info: {
    DVTErrorCreationDateKey = "2025-10-02 16:55:53 +0000";
    "com.apple.dt.DVTCoreDevice.operationName" = connect;
}
--
The tunnel connection failed while the system tried to connect to the device.
Domain: com.apple.dt.RemotePairingError
Code: 4
--

I get the same error via command line, e.g. for

xcrun devicectl device info apps --device "..."

My setup:

macOS Version 26.0.1 (Build 25A362)
Xcode 26.0.1 (Build 17A400)
iPhone 13 on iOS 26.0.1
iPhone is paired with the Mac (I can see it in Finder and in Xcode alongside the simulator).
Developer Mode is enabled on the iPhone.
I also see my Apple Watch listed in Xcode.

What I tried:

Restarted both Mac and iPhone, unpaired them, paired them again.
Disabled and re-nabled development mode
Tried both Wi-Fi and wired connection (Apple-certified cable).
Reset privacy and network settings on the iPhone.
Verified I’m not running any VPN.

Despite this, deployment always fails with the same tunnel connection error.

Has anyone encountered this before or found a solution/workaround?

Thank you very much,

Martin

(the device ID has been hidden)

[Edited by Moderator]

iPhone 13

Posted on Oct 3, 2025 2:42 AM

Reply

Answer 1

Top-ranking reply

SahilSingh16

Level 1

8 points

Nov 7, 2025 1:56 PM in response to MartinVonBahnhof

Problem

-------

Many developers run into a persistent “Tunnel connection failed” error when trying to connect an iPad or iPhone for debugging.

Even after reconnecting USB-C or Lightning and tapping “Trust This Computer” multiple times, the connection won’t establish.

The issue isn’t on the Mac — it’s the iPad not activating its tunneled connection properly.

What I discovered

-----------------

The iPad’s Developer Mode networking stack can become unresponsive.

By enabling a few developer networking options and **running the “Test Responsiveness” function**, the system restarts the underlying network daemons and reopens the tunnel instantly.

No reboot, no re-pairing, no resets required.

Prerequisites

-------------

- iPad with **Developer Mode** enabled

- iPad and Mac on the same Wi-Fi network (or paired once via USB for trust)

- Xcode compatible with your iPad’s iOS version

Steps to fix

------------

1. On your iPad, open **Settings → Developer**.

2. Scroll to **Networking** and turn on:

- **Network Link Conditioner** → **On**

- **Network Override** → **On**

3. Under the same **Networking** section, tap **Responsiveness**.

4. Inside that menu, tap **Test Responsiveness** and let the test run until it finishes.

- This test measures network round-trip speed but also restarts the iPad’s internal networking daemons (`mDNSResponder`, `configd`, and `developer_mode_agent`).

- While it’s testing, the iPad re-broadcasts its service and reopens the tunnel port (62078).

5. After the test completes, connect the iPad to your Mac (or keep it connected if it already is).

6. On the Mac, open **Xcode → Window → Devices and Simulators** and check **Connect via Network** for your iPad.

7. Wait 10–15 seconds. The iPad should appear with the small Wi-Fi icon — that means the tunneled connection is active again.

8. You can now unplug USB if you want to continue wirelessly.

Why it works

------------

- **Network Link Conditioner** restarts the iPad’s network discovery services.

- **Network Override** ensures developer connections aren’t throttled or suspended.

- **Test Responsiveness** directly forces the iPad to re-advertise itself to usbmuxd and reopen the tunnel listener.

- Once the test completes, the Mac successfully establishes the tunnel handshake.

Notes

-----

- This method works even if VPNs or custom network profiles are active.

- If the tunnel fails again later, simply repeat **Steps 3–4** (run **Test Responsiveness**) — it instantly repairs the connection.

- There’s no need to clear trusted computers or restart anything on the Mac side.

- The key is performing the **Test Responsiveness** action to wake the iPad’s developer networking stack.

This fix has been 100% reliable for resolving “Tunnel connection failed” on iPadOS.

Run the Responsiveness test, and the tunnel reconnects immediately.

Reply

Answer 2

Nov 7, 2025 2:07 PM in response to MartinVonBahnhof