Please ensure you’ve followed the steps exactly as described here: https://airlandline.com/pages/business-whatsapp-setup-instructions/
Pay particular attention to Step 2 as your Routing page needs to look exactly as we’ve shown in Step 2.
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 to your account, then remove the old one.
To add a new number to your account, head to Profile > Active Numbers > New Number +, or follow the link here.
Once you’ve added your new number, you can remove the old one by heading to Profile > My Subscription, or follow the link here. Then select the number that you wish to remove, and set the status to Cancel.
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.
If you have any questions, please contact our Support Team at hello@airlandline.com.