Please read, and reply back here with information https://forums.adobe.com/thread/1499014
-try some steps such as changing browsers and turning off your firewall
-also flush your browser cache so you are starting with a fresh browser
A chat session where an agent may remotely look inside your computer may help
Creative Cloud chat support (all Creative Cloud customer service issues)
I managed to get around the problem. I initially tried quitting CC, deleted opm.db, and restarting CC, but this didn't help. I then uninstalled and reinstalled CC, but no good. I finally got round the problem by quitting CC, renaming the folders AAMUpdating and OOBE and then restarting CC. The only problem with this was that I lost Lightroom 5.7 and had to download and reinstall it. Happily it kept all my images as they were.