I have exactly the same issue. It was working for some time and it stopped. Now it tells me to subscribe. Looks like it was some kind of free trail for Hulu with Spotify rather than Spotify Premium with Hulu :/
Then yesterday I went to go use Hulu on my Roku TV, and it asked me to connect/log in (something I’d already done upon purchasing the TV 2 weeks ago). After a few failed attempts to log in using the code (which had no response), I went to do it on my phone, I would plan asked if I wanted to (Re)subscribe.
I logged into my Spotify (to see if I could link them back up), and now there isn’t even the option to link them up because the promotion has passed. I’m at a loss at what to do.