Stuck on th2_release 10586 Core

I have been a Windows Insider since before the RTM days of Windows 10. I changed out the HDD in my laptop yesterday to an SSD and used an officially downloaded Windows 10 ISO to start off the SSD with a clean install. When I first attempted to turn on the preview builds in the settings, I kept getting the annoying FIX ME "Your security settings need to be updated before you can use preview builds blah blah..." I turned off preview builds and then immediately turned them back on. Now my Fast Ring setting is sticking, but when I go to update, the latest preview release is not being found by Windows Update, effectively leaving me stuck on 10586. I believe the latest preview release is 10.0.14267.1000 (14267 for short).