You open WhatsApp Web or WhatsApp Desktop, the QR code appears, and you hold your phone up to it. Nothing happens. Or the phone thinks for a moment and then says 'Couldn't link device'. Or your camera app reads the code and does nothing useful with it.
The QR code is a one-time handshake between your phone and the computer. For it to work, the phone has to read the code from inside WhatsApp, it has to be online at that moment, and your account has to have room for another linked device. Almost every failure is one of those three things, and the rest are the computer's browser getting in the way.
Start with the thing that trips up more people than anything else: where you are scanning from. Pointing your phone's normal camera app, or a QR scanner app, at the WhatsApp Web code does not link anything. The code has to be scanned from WhatsApp's own 'Link a device' screen. WhatsApp's help says that if scanning with the phone's camera doesn't open WhatsApp, scan from inside the app instead.
It is also not the same as the QR code icon next to your profile, which is for sharing your contact. That scanner is for adding people, not computers.
- Android: open WhatsApp, tap More (the three vertical dots), then 'Linked devices', then 'Link a device'.
- iPhone: open WhatsApp, tap 'Settings', then 'Linked devices', then 'Link a device'.
- If your phone asks for your fingerprint, face or PIN, that is WhatsApp verifying it's you. Complete it and the scanner opens.
- Point the phone at the computer screen so the whole code sits inside the frame, and hold still.
Cause 1: The camera can't read the code
WhatsApp's help on scanning QR codes lists a phone camera that isn't working properly as one of the reasons a scan fails. In practice that usually means the code is blurry to the phone, not that the camera is broken.
- Wipe the camera lens. A thumbprint smear is enough to stop it focusing on a fine pattern like a QR code.
- Move the phone further back. Held too close, many phones can't focus and the code fills more than the frame. Start at about arm's length and move in slowly.
- Turn the computer screen brightness up. WhatsApp gives the same advice for its chat transfer QR scan, along with cleaning the camera and removing a screen protector that covers the lens.
- Reset the browser zoom to 100 percent (Ctrl+0 on Windows, Cmd+0 on Mac) so the code isn't stretched, squashed or cut off at the edge of the window.
- Cut glare. A window or lamp reflecting off a glossy laptop screen can wash out part of the code. Tilt the screen slightly.
- If the code has been sitting there a while, reload the WhatsApp Web page to get a fresh one before you try again.
Cause 2: Your phone has no working internet connection
Linking happens through WhatsApp's servers, so the phone has to be online at the moment you scan. WhatsApp's help names no internet connection as one of the reasons a QR scan fails. A phone on weak mobile data, or on Wi-Fi that connects but doesn't actually reach the internet, can read the code and still fail to finish the link.
Check that you can send a WhatsApp message from the phone right now. If you can't, fix that first: switch between Wi-Fi and mobile data, turn airplane mode on and off, or restart the phone. If the computer is the one struggling, WhatsApp's connection help notes that office, school or public Wi-Fi can block WhatsApp Web, so try another network or a phone hotspot.
Cause 3: WhatsApp on your phone is out of date
WhatsApp's troubleshooting help repeatedly tells people to update WhatsApp to the latest version available in their app store, and an old version of the app is a common reason linking misbehaves. If the menu on your phone doesn't say 'Linked devices', or the 'Link with phone number instead' option is missing, that is a strong sign the app is behind.
Open the Google Play Store or the App Store, search for WhatsApp and tap 'Update' if it is offered. Then close WhatsApp fully, open it again and retry. If you use WhatsApp Desktop, update that app too.
Cause 4: You have hit the linked device limit
WhatsApp's help says you can stay connected by linking up to four devices at a time to your primary phone. WhatsApp Web in each browser, WhatsApp Desktop on Windows or Mac, an iPad and wearables all count. An old laptop, a work computer you no longer use or a browser you linked once and forgot about can quietly use up the four places.
When that happens the new link won't go through. Clear a space and try again:
- Open 'Linked devices' on your phone. It lists every device linked to your account.
- Tap a device you no longer use and choose 'Log out'.
- Go back, tap 'Link a device' and scan the code on the computer again.
- While you are there, log out anything you don't recognise. Someone else's computer in that list can read your chats.
Cause 5: The browser on the computer is the problem
Sometimes the phone side is fine and the browser never completes the handshake, or it shows the code and then reloads it endlessly. WhatsApp's help says WhatsApp Web works on the latest versions of Chrome, Firefox, Microsoft Edge, Opera and Safari, and not on some older browsers such as Internet Explorer.
- Update your browser to its latest version, or try a different supported one.
- Clear the browser's cache and cookies for web.whatsapp.com. WhatsApp's help lists this as a fix for WhatsApp Web connection problems.
- Turn off ad blockers, privacy extensions and VPN extensions for the page, then reload. A quick test is a private or incognito window, which usually runs without extensions.
- Make sure the browser isn't blocking cookies for the site. WhatsApp Web keeps your login in the browser's site data.
- Restart the computer if the page still won't settle. It is the same advice WhatsApp gives for connection problems: refresh, log out and back in, restart.
When the camera won't cooperate: 'Link with phone number instead'
If your camera is broken, cracked or just won't focus on the screen, you don't need the QR code at all. WhatsApp's help says you can link a new device either by scanning the QR code or by using your phone number. WhatsApp's own article on it describes the option on WhatsApp Web and WhatsApp for Windows.
- On the computer, open WhatsApp Web or WhatsApp for Windows and choose the option to log in with your phone number instead of scanning.
- Enter the phone number of your WhatsApp account. The computer shows a code.
- On your phone, open 'Linked devices', tap 'Link a device', then tap 'Link with phone number instead'.
- Verify with your fingerprint, face or PIN if asked, then type the code shown on the computer into your phone.
- You still need your primary phone for this. WhatsApp's help says you need your primary phone to register your account and to link new devices.
Prevent it next time
Most repeat trouble with WhatsApp Web is a link that quietly expired, not a new fault. WhatsApp's help says linked devices work without your phone being online but log out if your phone goes unused for a while, which most of its pages put at 14 days.
- Open WhatsApp on your phone at least every few days if you rely on WhatsApp Web or Desktop.
- Check 'Linked devices' now and then, and log out anything old so you always have a free place for a new computer.
- Keep the WhatsApp app, WhatsApp Desktop and your browser updated.
- Only link the official WhatsApp Web site and WhatsApp apps. WhatsApp warns that linking through unofficial apps or websites may put your account at risk.
- If WhatsApp says it found an unrecognised device and asks you to confirm the link, only say yes if that device is the one in front of you.
Making it easier for customers to reach you on WhatsApp
If you use WhatsApp for business chats, a free OneSol page gives customers one link that opens your WhatsApp chat, alongside your other contact options, so nobody has to type your number in by hand.