Cover Image

Kindly try adding the following code in the bottom of your theme’s functions.php file.

function aiovg_custom_player_css() {
echo '<style type="text/css">#player .vjs-poster { background: transparent !important; }</style>';
}
add_action( 'aiovg_player_head', 'aiovg_custom_player_css' );

Hope this solved your issue!

Thank so much. That solved it for the enlarged version but I also need it for the thumbnail. Is there code for that?

Yes. But, this is a PRO feature. Please refer https://plugins360.com/all-in-one-video-gallery/auto-thumbnail-generator/