If you receive a , it usually means the high-resolution version does not exist for that specific video.
: Only videos uploaded at 720p or higher typically generate a maxresdefault.jpg . Download maxresdefault jpg
Do you have the for which you need the thumbnail so I can generate the direct download link for you? If you receive a , it usually means
: Find the 11-character ID in the YouTube video's URL (the string after v= ). If you receive a