For iOS, I think there is a bug in the iOS Home App that sometimes prevents pairing.
I’ve found that these workaround methods often work:
Method #1:
Do a full power-off (unplug) all your Apple thread border routers and controllers (Apple TVs, HomePods, HomePod minis. Its pretty much the IT stereotype method (“Have you tried turning it off and on again”).
Method #2:
- Reset the switch using the Config+Paddle-Up 20 seconds until LED turns Red, then release, method
- Using the “Camera” app and not the iOS Home app, scan the QR code
- The iOS Camera app will then show a highlighted link to “Home” - tap on that
- You’ll then be asked to select your Home - do that and proceed to the pairing step.
I’ve found Method 2 often results in successful pairing even when you can’t pair directly from the iOS Home app. No reasonable explanation for this, but I’ve found it does work in a large number of cases where you can’t pair from within iOS. Hopefully, this will be fixed in iOS 18.
Method #3
Sometimes after a pairing failure, data is left in the iOS Keychain that causes problems with pairing. Go to iOS Settings (Gear icon) → General → Matter Accessories and look for a “dead” “VTM31-SN” entry. If you have paired multiple VTM31s, you can tell which ones are active by looking for the name of your iOS Home below the "VTM31-SN’. label - or click on the label which brings you to the “Connected Services” page → if there are no “Connected Services” that is probably a dead entry.
Use Method #1 and #2 first. Method #3 is a little risky in that if you do it wrong, you’ll delete an entry for a working switch, then have to remove and re-pair that switch all over again.