我仔细阅读了有关此错误的讨论帖。所有建议的解决方案（截断 /var/lib/ubuntu-release-upgrader/release-upgrade-available 或在 /etc/update-manager/meta-release 中将 https 更改为 http）均对我不起作用。
[xavier@imladris ~]$ sudo do-release-upgrade -d
Checking for a new Ubuntu release
Failed to connect to https://changelogs.ubuntu.com/meta-release-development. Check your Internet connection or proxy settings
Upgrades to the development release are only
available from the latest supported release.
我的网络没有问题，我甚至可以在浏览器中看到元发布文件。
有趣的是，它昨天运行正常，但我没有时间升级。此外，它在同一网络上的 BHve 主机上的 Ubuntu VM 上运行正常
所以这似乎是一个暂时性错误。 有没有办法永久修复它？
仅供参考，我的 motd ：
Welcome to Ubuntu 22.04 LTS (GNU/Linux 5.15.0-33-generic x86_64)
* Documentation: https://help.ubuntu.com
* Management: https://landscape.canonical.com
* Support: https://ubuntu.com/advantage
0 updates can be applied immediately.
感谢和问候，
泽维尔
编辑：我已经激活了调试模式，我得到了
[xavier@imladris ~]$ sudo do-release-upgrade -d -e DEBUG_UPDATE_MANAGER=1
Checking for a new Ubuntu release
MetaRelease.__init__() useDevel=True useProposed=False
/etc/update-manager/meta-release: http://changelogs.ubuntu.com/meta-release
/etc/update-manager/meta-release: http://changelogs.ubuntu.com/meta-release-lts
/etc/update-manager/meta-release: -development
/etc/update-manager/meta-release: -proposed
metarelease-uri: http://changelogs.ubuntu.com/meta-release-development
MetaRelease.download()
result of meta-release download: '<urlopen error [Errno -2] Name or service not known>'
Failed to connect to http://changelogs.ubuntu.com/meta-release-development. Check your Internet connection or proxy settings
NO self.metarelease_information
Upgrades to the development release are only
available from the latest supported release.
[xavier@imladris ~]$ sudo geany /usr/lib/python3/dist-packages/UpdateManager/Core/MetaRelease.py
[xavier@imladris ~]$ sudo do-release-upgrade -d -e DEBUG_UPDATE_MANAGER=1
Checking for a new Ubuntu release
MetaRelease.__init__() useDevel=True useProposed=False
/etc/update-manager/meta-release: http://changelogs.ubuntu.com/meta-release
/etc/update-manager/meta-release: http://changelogs.ubuntu.com/meta-release-lts
/etc/update-manager/meta-release: -development
/etc/update-manager/meta-release: -proposed
metarelease-uri: http://changelogs.ubuntu.com/meta-release-development
MetaRelease.download()
result of meta-release download: '<urlopen error [Errno -2] Name or service not known>'
Failed to connect to http://changelogs.ubuntu.com/meta-release-development. Check your Internet connection or proxy settings
NO self.metarelease_information
Upgrades to the development release are only
available from the latest supported release.
DNS 问题？我将 changelogs.ubuntu.com 放入 /etc/hosts 文件中，但没有成功
答案1
就我而言，在 Ubuntu 20.04 和 Ubuntu 22.04 上，这个问题是由配置引起的APT Proxy server（可能是代理服务器没有某些 SSL 根 CA 或其他问题）。
在注释掉代理配置后，/etc/apt/apt.conf.d/我的 Ubuntu 服务器升级启动顺利。