Plex only imports some iTunes playlists



I'm running OS X 10.11.6 on a mac mini, with my music library on an external hard drive. I want to import my iTunes playlists but when I try to do this all that is imported is 90s music, recently added, recently played and top 25 most played. No other playlist is imported. I have other playlists which are picked up in the "iTunes Channel" but they are not being imported into Plex. I only have the basic Plex account, not a Plex pass.
Can anyone point me in the right direction to resolve this, please?


Hunt around the forum for other posts on this. Plex doesn't import most smart playlists. :(


These aren't smart playlists - I'm aware of that issue - they are just ordinary playlists.