Is on a watch page?  No – the video is supplementary content on the page

Hello, we apologize for the issue you are facing. It seems like you are encountering a situation where Google is not recognizing your video as the prominent content on your page, possibly because it is considered supplementary.

To address this, you can follow these steps:

1. Ensure Your Video is Above the Fold: Make sure that your most important video is placed above the fold on your webpage. This means it should be visible without scrolling down. Google tends to index only one video per page, so placing the most relevant video at the top can help.
   

2. Resize Your Video: If your video is too tall or too small, it may not be indexed correctly. Ensure that the video height is 1080px or below and that both height and width are at least 140px each. The width should also be at least one-third of the webpage’s width.

3. Request Google to Reindex the URL: After making these changes, go to Google Search Console and use the URL Inspection tool to request indexing for your updated page. Click on REQUEST INDEXING after testing the live URL.
   

By following these steps, you should be able to help Google recognize your video as a more prominent piece of content on your page. If you have further questions or need assistance, please reply to this ticket, and a human agent from our support team will assist you.

Sources:
How to Fix ‘Google Could Not Determine the Prominent Video on the Page’ Error » Rank Math