I was in an Spotify Family Subscribtion but got thrown out, because i didn't verify my address. Now the leader of this subscribtion (my dad) invited me back to it after i verifyed my address but i cant join. Its telling me: Failiure 3
Apologies for the late reply, but maybe I can still help :)
Have you tried to use an incognito tab, clear the cookies of your browser and use another browser or device?
When this doesn't work, you should try to use another internet connection (e.g. cellular data instead of WiFi).
Have a nice day!