I implemented VNC server on my device (STM32F4), and it works OK with VNC client on a windows PC.

However when I try to use VNC app from my android phone, the display is black (cursor movements and clicks works from hand device).

I tried about 4 different VNC clients on my phone, all with same result.

Any Idea what could be the problem?

Thanks

I don't see such settings on the mobile app.

Is there a way to change encoding? I can see in the manual GUI_VNC_SUPPORT_HEXTILE , but can't find this constant in the library

I also o tested with ST discovery STM32F7 demo.
Same results. So it is not my code but something deeper.