Hello,
Sorry to hear about the inconvenience.
We have checked and confirmed this concern from the Test Site, we have added a YouTube Video on one of the Products and also added a Custom Tab on it having a Video uploaded from the Media and they both were working fine. Here is the Product URL from the Test Site: https://blackpearlspro.com/woodmart_support/product/augue-adipiscing-euismod/
So, this clears the fact that it is not a Theme end issue.
Also, the YouTube Video right now can’t be added through Custom Tabs. It can only be added through the Product Video area.
So, there might be some third party Plugin conflict on your Site regarding the YouTube Video not working or might be the YouTube Video URL isn’t correct. So, can you please provide valid WP-ADMIN Login details of your Site in the below listed format on which you are facing the issue so that we can look after the mentioned issue on your Site and assist you accordingly.
WP-ADMIN URL:
WP-ADMIN USERNAME:
WP-ADMIN PASSWORD:
Best Regards.