Tvheadend HTSP client buffering


I am not able to open any TV channels from my DVB-T USB tuner (Pinnacle 340e).

Everything seems to be OK: TVheadend server identifies channels, TVheadend HTSP client is activated and connected to the server, but when I click on a dedicated channel I receive message:

Tvheadend HTSP Client
No signel …

and I am not able to see Live TV.

Please help!