There have been ongoing issues. Take a look at this post and see if this solves your problem: Flame "No Internet Connection" - "Required Connection to Autodesk could not be established" Single User Login - #69 by randy
And yes, the ADSK identity team struggles with the Flame environment. They’re not familiar with it, or even Linux for the most part. Lots of us had their share of frustration with that team.
But then Flame is a forgotten step child of ADSK, stuck in the annex somewhere on the property. I’ve stopped counting the webforms where you have to write in Flame under ‘Other’ because it’s not listed, or the ADSK folks who never heard of Flame.