Receiving "You must accept the WhatsApp Business Cloud API terms to use the API." error on register phone number request

In our app, we are trying to use Whatsapp Cloud API with our user's OAuth access token (received through the Facebook Login flow, and we have whatsapp_business_messaging,whatsapp_business_management and business_management scopes).

The WABA is defined in their own business.

The issue comes when we try to use https://developers.facebook.com/docs/whatsapp/cloud-api/reference/registration/ this call to finish getting access to the phone number - we receive (#200) You must accept the WhatsApp Business Cloud API terms to use the API. Check your WhatsApp Account Overview page

I'm wondering if this is some kind of terms of service that I need to accept (can't see any prompt to do so on my end), or something that our clients should accept in their WABA?