HbbTv doesn't work with BH 2.1.5

[federal]

I cannot make HbbTV work on Vu+ Zero and BlackHole 2.1.5... On the Info bar ,the HbbTv sign turns orange displayin at its right in grey the name of the HbbTv service,so you 'd expect that HbbTv is active, but pushin the Red button does nothing and prolonged push on blue gives the choice of several HbbTV applications ( ZDF 19E) but if selected ,none of them works.
Am I missing something here ?
Thanks for any suggestion...