Instead of selecting “Custom” select “Stereo”. This has worked for many devices when the Dolby setting is showing a picture with no sound. So, within the Roku device, select “Settings” > “Audio” > “Digital output format” > “Stereo”. Make sure “Stereo” is checked and “Auto” and “Custom” is NOT checked. This setting works for many devices when the “Custom” is showing a picture with no sound.