Seeing quite a weird issue on multiple Linodes in their Sydney DC which essentially boils down to IPv6 being seemingly misconfigured on the Spotify end. I have tried but cannot replicate the issue on any other network I have access to.
Running curl -4 -v api.spotify.com works as expected and returns a 301 redirecting to https. Running the same command with -6 instead returns what looks like a 403 error from Google, so it seems that some part of the GCP backend is broken? Maybe a node behind a load-balancer that I'm just not getting routed to from my other networks?
I see pretty much the same behaviour with accounts.spotify.com, www.spotify.com and spotify.com, over http and https.
I've attached the output of the curl commands. I'm happy to be shown that it's an error on my end but from what I'm seeing that seems unlikely. In the meantime I've put a hosts-file override in to force the connections to IPv4.