If you see the yellow-green screen then there is nothing wrong with the video output of the NTB.
It is possible, in the "Screen Background" page on the NTB, to change the colour of the green screen,
if you are seeing that colour then the above still applies.
If you set the background colour to black then it will be difficult to determine what is wrong.
Browse to "Screen Background" and change it now to diagnose this fault.
The green screen usually means that there are empty playlists.
The NTB may be auditioning something. Browse to the "Schedule" page and click the "Activate Schedule and Layouts" button.
Screen is still green.
No e-mail? Layout Package too big? Phone 01491 845286.