Hello. Thanks for touching base. I reinstalled Spotify before I posted my first message. I also knew how then to create a new playlist. I still had problems but for a couple of weeks, and then things were better. Then this week back to square one. Today I installed the latest version of IOS and it’s working. My guess on the source of this problem is the interplay between the Spotify software and the iOS on my phone, both of which change on a regular basis.
I’ve noticed when I’m playing a song and try adding the song to a “NEW” Playlist is when I encounter this problem of not being able to create a new Playlist. If I pause the song or toggle my data connection off and on sometimes this clears up the problem and I can then open the song again and add it to a “NEW” Playlist. So, it seems this could somehow be a bandwidth, cacheing, communications or connection problem also. Try this, hope it helps.