Please ensure you’ve followed the steps exactly as described in this guide: https://airlandline.co.uk/pages/whatsapp-setup/
If the above doesn’t work, and you don’t mind changing your landline number, the quickest option is to try with a different landline number. To change your number, you simply need to add a new number then ask us to remove the old one. To do this, just use the “Buy Numbers” button at the bottom of the Control Panel to add a new number, then email us to let us know which number you’d like removed.
If you’ve had the landline number for a long time and so don’t want to change it, then you could wait a few days and try again. And if it still doesn’t work you could try contacting WhatsApp and send them a screenshot of the error message, although they typically respond with a generic response so you’ll have to reply a few times to let them know none of their response in the generic response apply, before a human looks at it: smb_web@support.whatsapp.com
Why is the WhatsApp set up not working?
Pay particular attention to Step 2 as your Routing page needs to look exactly as we’ve shown in Step 2.