This is a bit of a pithy response. However, I spent several hours of my *own* time now reading dozens of reports of the same exact issue on these very forums.
So far I have:
Downloaded the CC Cleaner and cleaned the ID credentials
Downloaded the CC Uninstaller, and then uninstalled/reinstalled CC Desktop
Used the CC Cleaner to uninstall all of my Adobe apps and reinstalled
Renamed the OOBE folder
Deleted the OOBE folder
Changed my account password
Run the application as administrator
Run the application on a different local account
Restarted the WMI service on Windows
Restarted the Credentials Manager service on Windows
Verified my Internet Explorer settings (despite the fact that I don't use it)
They have repeated steps 1, 2, 3, 4, and 6 with me and then were unable to help further. NOTE: They have repeated steps 1 and 2 at least 4 times, apparently expecting it to suddenly solve the problem.
Next step, I think, is to cancel my plan and stop paying for software that doesn't function? Apparently, the last support tech that repeated steps 1 and 2 told me they would escalate the issue and I'd have someone call me back within 48 hours. So far my Adobe subscription has cost me nearly 8 times its cost in lost productivity.