You can't use the clientless feature with the HTML5 Gaterway when NLA is enabled. This is a great feature of the HTML5 gateway however disabling NLA is not an option. Would be ideal if this can be rectified and get the HTML5 gateway working with NLA enabled.
Sergio, we will introduce Network Level Authentication (NLA) support in HTML5 Client in v16 release next month. v16 is out in beta now, let me know if you are interested in testing.
Thank you for the info. We will wait until v16 is released as it's not critical at the moment but to properly use the HTML5 gateway, we need to leave NLA enabled for security reasons.