"Sorry, this content could not be embedded" error in WordPress Gutenberg?

You are trying to insert youtube in url field.

click the "Embeds" dropdown, you will get options for inserting "Youtube", then it will work

Check the image attached

This issue is because the youtube video that you are trying to embed in WordPress has disabled the "Allow Embedding" option.

https://i.stack.imgur.com/rQ0C5.jpg (Please view the following image for clarity)

If the youtube video creator/uploader has disabled this feature then you cannot embed those videos on any of the sites.

To embed a youtube video or another object into a WordPress post or page, place its URL into the content area. Make sure the URL is on its own line and not hyperlinked (clickable when viewing the post).

For example:

Check out this video:https://youtu.be/kK4ah2PgSnQvideo description.

WordPress will automatically turn the URL into a YouTube embed and provide a live preview in the visual editor.

• You can copy the YouTube URL for a video that you want to embed.

• Next, edit the WordPress post or page where you want to add the video, and simply paste the URL in the content area.

• As soon as you paste the video URL, WordPress will fetch the embed code and display the YouTube video inside the content editor.