Hello,
The ITAM REST APIs (https://docs.flexera.com/FlexeraOneAPI/ITAMDataAPI/) now works with UAT org. With this release, pass the UAT org id when you call the ITAM REST APIs.
Side note: we will be deprecating beta.api.flexera.com (.eu for EMEA) URL soon for the APIs, if you are still using "beta", simply drop the "beta" and use URL api.flexera.com (.eu for EMEA). Flexera One APIs are documented https://developer.flexera.com/.