Eagerly waiting for a solution !
- try to run the software as administrator - (right click->run as administrator)
- try disabling firewalls or antivirus/malware scanner and see if that works
- try reset your preferences: Reset After Effects Preferences
- re-install the application
I have the same issue and also tried completely reinstalling the software. For me the issue appeared when I updated from 2015.3.
Everything else is the same as prajithm77109048 reported.
I got the problem resolved with the help of Adobe customer care. steps taken to resolve are
1) First close all adobe applications running
2) Go to Task Manager and kill all the processes related to adobe .make sure that below mentioned are also killed (if any are running)
Adobe Crash demon,
Adobe Desktop Service,
3) Go to Run and type appdata.
4) Navigate to Local > Adobe > OOBE
5) Delete OOBE folder [if you are unable to delete that means there are still some processes running . go to taks manager and kill them ]
6) After successful deletion relaunch the Creative Cloud
now it will ask you for uid and pwd. enter valid id pwd and you are in.