I have been using Tidal as part of my Plex program for several months. In the last few days, when I click on “Music in Tidal” in my navigation window, the display is an invitation to sign up for an account, though checking my Plex account confirms that I am subscribed both to Plex Pass and to Tidal. I can access my Tidal account through the Tidal app on both desktop and Android phone, but not through Plex. I seen mention of “linking” a Tidal account to Plex, but no instructions on when it is necessary or how to go about it.
The instructions you pointed me to apply to people who do not have a Tidal subscription through Plex currently, which I do. I am attempting to cancel that subscription now and see whether I can then either start with a new subscription or link to my existing Tidal subscription. It sure is a mess. It should never be necessary for a paying subscriber to spend the time I have spent merely trying to enjoy the benefit he has paid for.