Sadly, one thing we have come to understand as achievement hunters is that, sometimes, a server goes down, never to appear again. There are many, many examples of this, though the one we'll be looking at right now affects Guitar Hero: World Tour
. See, somewhere around two years ago, the game's servers went offline without warning, thus discontinuing the following two achievements:
Thankfully, there is the occasional server closure that actually has a somewhat happy resolution, meaning that the server is restored for some period of time for people to have that last opportunity to get the achievements they need for completion. Thanks to the efforts of Holiday9357
and many others who contacted Activision and signed petitions and so forth, the servers for World Tour
are currently up, and we can confirm those formerly discontinued achievements are now available.
Hurry forth, rhythm game enthusiasts, and upload and download the necessary tracks. We don't know if this is a temporary revival or a permanent one, so it's best to treat it as if it won't be around forever and get the achievements done.