Thumbnail issues when embedding a YouTube video
Make sure you're adding the YouTube video to your page correctly. When embedding a YouTube video, copy the embed link via Share > Embed.
You only need the following piece of code: https://www.youtube.com/embed/videocode.
Note that sometimes extra parameters are added to this link: these start with either & or ?.
For example: ‘&feature=youtu.be’ or ‘?si=n9Do0u8CAPQqs3H_’.
Remove these parameters so that only /embed/videocode is left.
For example: https://www.youtube.com/embed/kXUHzpVO_Ug
How to add the thumbnail of your YouTube video to a call to action button
If you add a call-to-action button to your page with an embed link to your YouTube video, the CTA should automatically display an image. This image is the same as the thumbnail of the YouTube video.
However, sometimes no image appears, and the CTA on your webpage remains greyed out.
This could be because your video was not recorded in HD. If the video is recorded in HD but the image still doesn't come through, the following fix is recommended. On Youtube, go to Creator Studio > Video Manager and change the thumbnail to one of YouTube's three generated thumbnails, save and close the page. Repeat these steps to change the thumbnail back to your original image, and try embedding the video on your page again.
If this fix doesn't work, you can add your own image to the CTA. Note that the required dimensions differ from a regular CTA image. The image should be 4000 px W x 2240 px H or 2000 px W x 1120 px W.