Hello,
I have recently setup RemoteApp and a RD Gateway on a 2008 R2 Standard server. The server is in the DMZ and has 80/443 open to the internet. I have created a self signed cert with the name rdweb.mycompany.com which matches the public DNS entry that was created for the site.
I am able to access the site internally and externally, launch RDP sessions successfully, as well as connect RemoteApps that I have deployed via both RDP files and MSI files. The only piece missing is when I attempt to click on a RemoteApp Program from the site I get the error "RemoteApp Disconnected - Your computer can't connect to the remote computer because an error occurred on the remote computer that you want to connect to..."
No error logs are created on either the server side or client side. As far as I can tell my setup is correct according to technet articles that I have followed in order to get everything up and running.
One note, the RemoteApp Programs work fine internally if I check the box "Bypass RD Gateway server for local addresses." With this unchecked the RemoteApps fail to launch internally with the same error.
I have read through the forums as well as explored the net and have yet to find a solution.