iPhone and GoPro 8 are paired, Wi-fi is connected, but getting error and unable to see preview

Hi! Anyone know if it's possible to select a frame / image to show as the thumb preview for the final mp4 file?

I have just update the F/W on my Hero 3 Black and updated the GoPro App on both my iPhone 4S and iPad2 and I have not been able to get the Preview or Files View to start... I can control everything else from either device but cannot see the preview or access the files on these devices. I tried...