Logitech closed mysqueezebox.com in March 2024. For most people this changed nothing, because Squeezebox players always got their music from server software running at home. The website was an extra.
If you only ever used the website and never ran a server, install Lyrion Music Server. It’s the old Logitech Media Server, now kept going by the community. It runs on Windows, Mac, Linux, a NAS or a Raspberry Pi, and most players find it by themselves once it’s running.
Remote access from outside the house is gone unless you set it up yourself. A few streaming services that only worked through the mysqueezebox.com account may not come back, but Lyrion has plugins for a lot of others.