did you follow the guide?
DirectAccess enables remote users to access shared resources, web sites and applications on an internal network without connecting over a VPN. To support DirectAccess, the Horizon FLEX virtual machine must be running Windows 8.1 or later. The Horizon FLEX server must be deployed on Windows Server 2012 or later. The Active Directory server must be configured to support DirectAccess. For more information, see the Microsoft documentation.
Yes, followed the guide. Wasn't successful. However, the issue was further investigated and contributed to the blob size fix in 1.9.
We have exactly the same problem, did you manage to get this working ? We suspect its the way the GPO for DA is configured ?