问题描述：
Ubuntu登陆首页后提示如下信息：

Failed to connect to https://changelogs.ubuntu.com/meta-release-lts. Check your Internet connection or proxy settings

解决：
1.移除

sudo rm /var/lib/ubuntu-release-upgrader/release-upgrade-available

2.运行

sudo ./usr/lib/ubuntu-release-upgrader/release-upgrade-motd

出现”command not found“，忽略！
3.测试

sudo apt-get upgrade   #更新软件

sudo apt-get update与sudo apt-get upgrade的区别
https://blog.csdn.net/The_Time_Runner/article/details/105027539

成功解决！