ssh连接ubuntu之后出现Failed to connect to https://changelogs.ubuntu.com/meta-release-lts. Check your Internet connection
解决方法如下：
（1）移除 ： /var/lib/ubuntu-release-upgrader/release-upgrade-available
root@localghost~# rm /var/lib/ubuntu-release-upgrader/release-upgrade-available
（2）运行 ： /usr/lib/ubuntu-release-upgrader/release-upgrade-motd（.后应该是没有空格的，不太确定了）
root@localghost~#./usr/lib/ubuntu-release-upgrader/release-upgrade-motd
（以root身份执行，我的在运行release-upgrade-motd后出现“command not found”，不过不影响）
重新连接不再显示。
参考：
https://blog.csdn.net/qq_37232731/article/details/93355043 https://blog.csdn.net/qq_38066812/article/details/119538807
