is it possible to install HTML access after having already deployed the connection server without this option ?
Seems that there is no standalone installer and the only way is to uninstall and install again the whole connection server, just asking if someone can confirm.
I ran into the same issue and the only solution I could find was a uninstall/install. This isn't a big deal since the data is stored in the database (just make sure not to remove it).
Just to add that I had the same problem. Only solution I know of is to uninstall it completely and reinstall. As BenFB said, do not remove the AD LDS database. See screenshot
No way to install HTML Access separately so far.
To install HTML Access, you need uninstall Horizon Server without removing database, then reinstall with HTML Access option checked.