VNC Viewer (RealVNC) closes after connecting to VNC server
RealVNC's ColorLevel pal8 is not supported by most VNC servers, but the issue can be fixed by changing the ColorLevel value to full, rgb332, or rgb565 in the Expert tab of the RealVNC options menu.
VNC Viewer from RealVNC uses "ColorLevel" pal8, which is not supported by most VNC servers.
Please follow these steps in order to connect successfully:
Open the RealVNC options menu
Click "Advanced Options" near the bottom left corner of your app.
Click on "Expert" tab and change "ColorLevel" value from its default setting to full, rgb332 or rgb565
You should be able to successfully connect now.