Running but nothing on FFT display

Hi, I have one RTL-SDR and in my home computer it is working well. Now I am tryint to run in my office. Here is Ubuntu 14.04 and GNU Radio 3.7.8... For a simple flowgraph just with RTL-SDR Source and a FFT Sink I can't vizualise nothing in FM (88 - 108 MHz). I have also here a USRP and a BlackRF and both oof then are working well. Is there something to solve this? This is the output of Terminal to rtl_test -t Found 1 device(s): 0: Realtek, RTL2838UHIDIR, SN: 00000001 Using device 0: Generic RTL2832U OEM Found Rafael Micro R820T tuner Supported gain values (29): 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6 Sampling at 2048000 S/s. No E4000 tuner found, aborting. And this is the output of GNU Radio. [image: Imagem inline 1] Thanks so much, -- .: José Perez Jr