Did you miss Spotify's Developer Access and Platform Security update?

I noticed that my Spotify @Raycast extension had stopped working and discovered that Spotify clamped down on its platform as of last month:

Over time, advances in automation and AI have fundamentally altered the usage patterns and risk profile of developer access, and at Spotify's current scale these risks now require more structured controls.

In response, we are making changes to Spotify for Developers to better protect creators, partners, listeners and the platform. These updates build on changes we've implemented in the past, including the introduction of developer modes, refining access for WebAPI endpoints, introducing new extended quota mode criteria, as well as deprecating outdated OAuth flows.

Thus if you notice other Spotify-based products not working correctly... you might see if it's because of this.

Fortunately there's a handy Migration Guide devs can refer to.