Same here, i just get a blank import screen.
Also i dont think the Logout of Origin is working correctly. As you said to logout and log back in i tried that, Launchbox says i'm now logged out via a popup window, but when i go to try the importer again it still auto logs me in. I did check the box for "remember me" when i logged in the first time, so i guess it doesnt matter if i logout via Launchbox as it still auto logs me in after. Even after doing that i still get a blank import window.
Also i should add i have 2FA on so had to input my authenicator code, could that be messing with things?
For the record.