停止使用 Ubuntu Pro 并将机器恢复到使用 Ubuntu Pro 之前的常规配置的过程是什么？
我已经执行了“sudo pro detach”，它说它已删除它，并且我已经检查了我的 Ubuntu One 帐户。
mark@science2:/etc/apt$ sudo pro status
SERVICE AVAILABLE DESCRIPTION
anbox-cloud yes Scalable Android in the cloud
esm-apps yes Expanded Security Maintenance for Applications
esm-infra yes Expanded Security Maintenance for Infrastructure
livepatch yes Canonical Livepatch service
realtime-kernel yes Ubuntu kernel with PREEMPT_RT patches integrated
usg yes Security compliance and audit tools
For a list of all Ubuntu Pro services, run 'pro status --all'
This machine is not attached to an Ubuntu Pro subscription.
See https://ubuntu.com/pro
mark@science2:/etc/apt$
但是 sudo apt update 似乎显示仍有东西悬而未决：
mark@science2:/etc/apt$ sudo apt update
Hit:1 http://packages.microsoft.com/repos/code stable InRelease
Hit:2 http://us.archive.ubuntu.com/ubuntu jammy InRelease
Hit:3 https://repo.steampowered.com/steam stable InRelease
Hit:4 http://security.ubuntu.com/ubuntu jammy-security InRelease
Hit:5 http://us.archive.ubuntu.com/ubuntu jammy-updates InRelease
Hit:6 https://dl.google.com/linux/chrome/deb stable InRelease
Hit:7 http://us.archive.ubuntu.com/ubuntu jammy-backports InRelease
Get:8 https://esm.ubuntu.com/apps/ubuntu jammy-apps-security InRelease [7,553 B]
Err:8 https://esm.ubuntu.com/apps/ubuntu jammy-apps-security InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY AB01A101DB53907B
Hit:9 https://ppa.launchpadcontent.net/heyarje/makemkv-beta/ubuntu jammy InRelease
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
All packages are up to date.
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://esm.ubuntu.com/apps/ubuntu jammy-apps-security InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY AB01A101DB53907B
W: Failed to fetch https://esm.ubuntu.com/apps/ubuntu/dists/jammy-apps-security/InRelease The following signatures couldn't be verified because the public key is not available: NO_PUBKEY AB01A101DB53907B
W: Some index files failed to download. They have been ignored, or old ones used instead.
mark@science2:/etc/apt$
提前致谢