This problem resurfaced in my Windows 10 VM which I need in order to use Autodesk Motionbuilder since that is not available for MacOS. I once again was presented with a blank white login screen after entering my site in ShotGrid Desktop. I reinstalled ShotGrid Desktop but that did not help. I logged into RV without issue but that did not give me a session key. I then started clicking around in the blank white login screen for ShotGrid Desktop noticed the curser change to a text input so I typed in my Autodesk ID email and pressed enter. Then I located again the text input curser and typed in my Autodesk ID password and pressed enter. It worked! I am now logged in and am able to work. Hope this helps others. REALLY Hope Autodesk fixes this problem we are having.
PS. This same method allows me to login to ShotGrid Create in my Windows 10 VM which was also giving me a blank login screen.