post https://emailapi.netcorecloud.net/v6/messages/download
Assigns a domain to a subaccount so it can be used independently under that context.
Endpoint: POST https://apieu.netcorecloud.net/v6/domains/allocate
Notes
Ensure the domain exists and is available before calling this endpoint.
Each domain can be allocated to only one subaccount at a time.
You must have valid credentials and appropriate permissions for the sub-account.