Hello,
Please edit Hot Maps plugin file:
/wp-content/plugins/plugin_hot_maps/hotmaps.php and change http to https. In this line change this:
$html.='<iframe width="'.$hotmaps_params[1].'" height="'.$hotmaps_params[2].'" frameborder="0" scrolling="no" marginheight="0" marginwidth="0" src="http://maps.google.com/maps?q=';
to this:
$html.='<iframe width="'.$hotmaps_params[1].'" height="'.$hotmaps_params[2].'" frameborder="0" scrolling="no" marginheight="0" marginwidth="0" src="https://maps.google.com/maps?q=';
Best regards,
Milos