Help please: Creative Cloud deletes Typekit fonts right after syncing with Typekit

I am running Photoshop CC and Illustrator CC on Windows 10 and cannot access any TypeKit fonts. Here is my workflow:

1. Run Adobe Creative Cloud
2. Navigate to Typekit.com (Assets -> Fonts -> Browse Fonts from Typekit)
3. Select a font and sync.  The font shows up as having been synced in Typekit. (This "synced" state persists on Typekit.com after I exit and return to to that site, so Typekit is correctly tracking my font selections.)
4. Back in Adobe Creative Cloud, after about 5 seconds. I get an alert popup with the message "Font {whateverFontIJustSynced} has been removed."  The font never shows up in Photoshop or Illustrator.

I looked in the CoreSync-yyyy.mm.dd logs, and every sync failure is accompanied by two error messages:

20170129-133701.143: t=24cc: Info: [livetype] Setting x-access-token header for font download.

20170129-133701.154: t=2640: Error: [livetype] AddFontResourceEx failed, code=0

20170129-133701.154: t=2640: Error: [livetype] Failed to activate font

20170129-133701.154: t=2640: Info: [livetype] synced fonts

My hunch is that this a a permissions problem: specifically, Creative Cloud does not have write access to the %windir%\fonts folder. I'm not sure if that's where the fonts should end up, but they definitely not getting installed locally.  I tried running Creative Cloud as an administrator but it doesn't seem to make a difference.

I've tried several solutions to similar reported problems that seem remotely related: stopping and starting the app, rebooting, toggling font syncing. Nothing is working. Any ideas?

Thanks in advance...