Thanks for digging into it — I looked as well and couldn’t find any logs related to my FAB captcha problem either.
At this point, I’m convinced the issue isn’t on my end, but rather something server-side — likely in the auth flow for
!!!new!!!<— 
^^^^^^^^^^connections through the Fab plugin in Unreal Engine, or some related interface.
I’d recommend escalating this to the Epic Games devs or the Fab team — whoever’s currently responsible for maintaining the Fab plugin in UE.
– from a user who insists it’s not his fault 