I first did an upgrade in my lab from 2012r2 to ServerTP. DA worked but no changes could be made to the config anymore.
Also, the clients began complaining about connectivity even if the infrastructure tunnel still worked.
I then scrapped the config all together and ran the config again. Now, even the IPHTTPS failed and no clients could connect at all.
Then I decided to do a fresh install instead and scrapped the upgrade install all together. Set up the new config on a fresh install and still got the initial problem again. Once the config has been set, it cannot be edited with the GUI anymore.
The error message is as seen below: (DirectAccess configuration settings stored in GPOs cannot be backed up. Verify network connectivity to the domain controller.)

Any ideas? I am thinking this is a preview bug since even the RSAT are missing the remote access parts.