Waveshare 5 inch and raspberry PI

[dvo]

maybe you find here your anwsers :

[PLUGIN] Touch Display

I used the Volumio image ready made from Audiophonics to match my DAC. I want to use a waveshare 5.5" Touch Screen. I installed the Touch Plugin and turned the scree 90 degrees. I can see the mouse and the touch function works correctly however the screen just shows a grey surface (execpt for the mouse curser, which is white). what could I check to find out the reason for the mailfunction ? Bjoern