运行 Xubuntu 14.04LTS
最初，我收到以下错误
E: GPG error: http://mega.nz ./ Release: The following signatures were invalid: NODATA 1 NODATA 2
做了这个答案告诉我要做的事情，再次尝试更新。新的问题出现了。
E: GPG error: http://mega.nz ./ InRelease: Clearsigned file isn't valid, got 'NODATA' (does the network require authentication?)
我该如何解决？