Please refer to :
"Unknown Server Error" when you attempt to log in to Adobe Creative Cloud
"Unknown Server Error" - That's what the CC program says when I try to log in! Help!
Creative Cloud "Download Error" message
Which operating system do you have?
- Close the Creative Cloud application.
- Navigate to the OOBE folder.
Windows: [System drive]:\Users\[user name]\AppData\Local\Adobe\OOBE
Mac OS: /Users/[user name]/Library/Application Support/Adobe/OOBE folder - Delete the opm.db file.
- Launch Creative Cloud.
Hope this helps you.
Regards
Rajshree