POST
https://api.us.nylas.com/v3/domainsCreate domain
Registers a domain to your organization. To set up authentication, see Create an IAM API key for domains.
New domains start unverified. Before you use one with Transactional Send or Agent Accounts, verify its DNS records.
Nylas rejects fields other than name and domain_address.
Requires an IAM API key with the domains.create permission. Application API keys and access tokens don't work.