It seems that the "Picture in Picture" (PiP) feature is not currently available for the HTML video element you're using. The error message "Failed to execute 'requestPictureInPicture' on 'HTMLVideoElement': Picture-in-Picture is not available" indicates that the browser or platform you're working with does not support this specific PiP functionality for videos.

Picture in Picture mode typically allows you to watch videos in a smaller overlay window while continuing to browse or interact with other content on the main screen. To use this feature, you might need to check if your browser or platform supports PiP for HTML videos, or if there are any specific requirements or settings that need to be configured.

If you believe that your browser or platform should support PiP and you're still encountering this error, you could try updating your browser to the latest version or exploring any available documentation or forums to troubleshoot and resolve the issue.

Keep in mind that the availability of PiP functionality can vary depending on the technology stack, browser version, and platform you're using.