Hey there,
I can replicate this issue when you put only Youtube domain.
https://www.youtube.com/
https://www.youtube.com/?hl=it&gl=IT
But if you share the youtube video link, it will get correctly the thumbnail, you can refer on my attached screenshot below.
By the way, It looks like your Easysocial subscription has expired and in order for you to continue requesting for support, you will need an active subscription. If you have already renewed, please let us know so that we can correct this for your account.
Thank you for understanding.