Repro:
1. Launch and sign in to the Editor
2. Activate if needed
3. Navigate to Manage license window
4. Choose to activate Personal Edition
5. During activation loose network connection
6. On the Work offline window sign out from the account
7. Close Manage license window
8. Restore network connection
9. Wait few minutes before accessing Manage license dialog again
10. Observe empty window

I reproduced this issue twice out of 4 attempts.

Editor needs to be restarted to fix this empty window error.