Your Cloud UM comes with a pre-configured REST-Proxy. The following endpoints are whitelisted out-of-the-box:
Newsletter tracking
Newsletter App
Contactform 2
OneClick-Unsubscribe
Retrieving list of Lists (for e-Spirit integration)
Sending Newsletters (for e-Spirit integration)
Monitoring for reliable Cloud operation
If you need to whitelist additional REST endpoints, please contact our support team.