Lightroom API catalog request returns Error 404

[KurtTheBerner]

I'm working with Lightroom Classic and I synchronize some collections with the cloud. Everything works fine, I can access these cloud based photos using a browser. Now I would like to access these cloud photos using the Lightroom API. I can successfully authorize/login using OAuth2 and get an access token, but the catalog request (https://lr.adobe.io/v2/catalog) always returns error 404.
What is the problem? Does the Lightroom API not work with Lightroom Classic synchronized collections? Do I need the Lightroom Cloud version?

Thanks for help.
Kurt

[johnrellis]

There may not be anybody expert in the Lightroom API in this forum (or any Adobe forum, for that matter). Years ago I started playing with it, but it was quite crippled in its capabilities and I couldn't find any Adobe forum where an employee (or anyone knowledgable) would answer questions.  I don't know if that's changed since, but I suspect not.