Bizarre. The dropdown should show a list of devices Spotify is open on, and should throw an error if no devices found but activate is clicked. Does the rest of the metadata load right? Maybe the link you pasted wasn't what was expected. Your link has to come from clicking Share->Copy Song Link on Spotify.
I ran into the same issue out of nowhere with my Spotify app a few months ago- after hitting around 300 users. Apparently, Spotify has a limit [0] on their API quota for auth (around 25 users or so in theory), but don't feature the limit very prominently in their documentation.
Have you requested and obtained a quota extension? I gave up on my app altogether after a couple of weeks and seeing in their documentation "[this] review process can take up to six weeks."
Oh no, I didn't know about this. It looks like Spotify hasn't authorized anybody but me and I would have to add every user I want to add individually. I don't think that anybody has been able to use this app. If anybody really wants to try it out you can DM me on X https://twitter.com/thelukew3 or follow me there and I'll post an update when it's fixed. Maybe I'll relaunch next year. Thanks for the help.
