When you change servers / hosting the name of the path most likely has changed. For me the path on hosting server “X” was home/mysites/public_html/nameof the site/wp-content/plugins/etc.
On my new server is was home/something else/public_html/nameof the site/wp-content/plugins/etc.
I went to settings in the admin panel and changed the media path to home/something else/public_html/nameof the site/wp-content/plugins/etc. and it fixed it.
//YouTube Lightbox & SSL/HTTPS//
@jason P I am wrestling with an issue you stated in another forum you had the answer too. You said if anyone wanted to learn what it was to contact you, but that topic is closed. I need to learn what you did please.