After I login to the Facebook account and redirect to the login window in ArcGIS Pro, the window closes and ArcGIS Pro application then just quits immediately, I've tried clearing the cache and the only option I have is to login using Facebook. I have also changed the default browser on my pc from Opera to Edge but the same problem occurs?
Yes, I've tried Edge and Chrome, it seems as though another person had the same problem as me,
but I can't add new members to my organisation as I am limited to 1 member so I can't create a username/password account to login successfully, i don't think the problem is on my end.
I am a tech support at ESRI and today I have assisted a user who is having the same issue. Initially, it is a BUG and it is fixed now. The resolution is to install the patch, ArcGIS Pro 2.8 Patch 2 (2.8.2). I hope this helps and works for you as well.