Please refer the documentation on the problem you are facing.
Additionally you may try the below mentioned steps:
1. Win: Navigate to C/users/User Name/AppData/Local/Adobe/OOBE and delete opm.db
2. Mac: Navigate to ~/Library/Application Support/Adobe/OOBE/opm.db and trash it.
Launch CC desktop and try to sign in.
Also, refer the following forum thread on same subject for more information.
Hope this helps.