That means you need to link your other devices again. Users need to note here that once you opt for the Multi-device meta version, a message will pop up which will mention that all the previously connected devices will be unlinked. Once logged in, even if your primary device, the mobile, is switched off, you can still WhatsApp on the other devices. Then move ahead to link a device and then scan the QR code. If you haven't joined the ‘Multi-device meta' version, then you need to join that first. It will ask you to scan a QR code from the web version of WhatsApp. Then click on “Linked Devices” and within that select “Link a Device”.
