Got the same error using the web player in Firefox 91.10.0 ESR. Tried logging out and back in as suggested in support resources - did not help. The first re-login attempt failed, I was logged in only after a long reload (~30 seconds or more), but the problem persists: trying to play a playlist or an individual song does not work and shows the "Something went wrong with the playback" message.
The reality of these sorts of problems is not "blame the user" like Spotify support likes to do. Rather, the reality is that Spotify Engineering doesn't know what they're doing.
There are tons of issues with the various Spotify clients because resources cannot be loaded over the network within a certain timeout. When you're on gigabit fiber this gets old really fast. But Spotify was not architected by savvy engineers. Loading static (or relatively static) content should be at the network edge and be blindingly fast on a good network connection.
For me, Spotify cannot even reliably load my own playlists. It times out and tells me the playlist doesn't exist. This message directly translates to "Spotify doesn't know how to code".
We understand that things can feel frustrating when Spotify doesn't work as it should. However, we haven't been able to see any recent trends about this which is the reason we'd like to start with troubleshooting this individually.
To start with, can you let us know if this occurs on one specific device or multiple devices?
Obviously, customers don't have the ability to implement distributed telemetry into the Spotify client, all of Spotify's overly complex GCP stuff, and anything else that's relevant, and then analyze the telemetry track down network-related issues.
Spotify doesn't know how to implement and use telemetry if they cannot see this issue. There are probably a lot of intermittent tail events that impact customers that Spotify is completely unaware of. But of course they exist. Because customers keep posting about them here and many other places on the web.
So maybe other than using the standard support script, go into the telemetry logs and pull out some tail events and ask yourself what they mean for users. If you don't know, then find out.
You know, basic software engineering. That thing that Spotify likes to talk about but seems to have such a hard time doing.