iTunes Shuffle won't work on some playlists

I have the new iMac (Sept 2017) and my iTunes Library transferred correctly, but some playlists won't shuffle. Hitting the shuffle (upper right) does nothing. Other playlist shuffle with no problems. I checked the repeat function and it is off. I transferred the songs to a new playlist, but the new playlist won't shuffle either.

Look forward to your suggestions.

Thanks - Hank