apt-get更新GPG错误

我一天中大部分时间都在寻找解决方案，但我的所有谷歌搜索都没有任何适合我的情况的结果。

我有一台运行Ubuntu 16.04.3 LTS（4.4.0-98-generic）的服务器。

今天，我使用“ apt更新”和“ apt升级”更新了系统。没问题。在此之后，我想删除owncloud，因为我只是对其进行了简短的测试。我试图运行“ apt remove owncloud”，但是由于某种原因它什么也没做。然后，当我通过能力决定并成功将其删除时。

在此之后，为了仔细检查，我再次运行了“ apt update”。

这次我遇到了多个错误：

    Get:1 http://mirror.netinch.com/pub/mariadb/repo/10.1/ubuntu xenial InRelease [3,874 B]
0% [1 InRelease gpgv 3,874 B] [Connecting to fi.archive.ubuntu.com (91.189.88.161)] [Waiting for headers] [Waiting for headers]Splitting up /var/lib/apt/lists/partial/mirror.netinch.com_pub_mariadb_repo_10.1_ubuntu_dists_xenial_InReleaseErr:1 http://mirror.netinch.com/pub/mariadb/repo/10.1/ubuntu xenial InRelease
  Clearsigned file isn't valid, got 'NODATA' (does the network require authentication?)
Get:2 http://security.ubuntu.com/ubuntu xenial-security InRelease [102 kB]
Get:3 http://ppa.launchpad.net/ondrej/php/ubuntu xenial InRelease [23.9 kB]
Err:3 http://ppa.launchpad.net/ondrej/php/ubuntu xenial InRelease                   Splitting up /var/lib/apt/lists/partial/ppa.launchpad.net_ondrej_php_ubuntu_dists_xenial_InRelease into data and signature failed
  Clearsigned file isn't valid, got 'NODATA' (does the network require authentication?)
Get:4 http://fi.archive.ubuntu.com/ubuntu xenial InRelease [247 kB]
Err:2 http://security.ubuntu.com/ubuntu xenial-security InReleaseting up /var/lib/apt/lists/partial/security.ubuntu.com_ubuntu_dists_xenial-security_InRelease into data and signature failed
  Clearsigned file isn't valid, got 'NODATA' (does the network require authentication?)
Get:5 http://security.ubuntu.com/ubuntu xenial InRelease [247 kB]
Err:5 http://security.ubuntu.com/ubuntu xenial InRelease    Splitting up /var/lib/apt/lists/partial/security.ubuntu.com_ubuntu_dists_xenial_InRelease into data and signature failed
  Clearsigned file isn't valid, got 'NODATA' (does the network require authentication?)
Err:4 http://fi.archive.ubuntu.com/ubuntu xenial InReleaseg up /var/lib/apt/lists/partial/fi.archive.ubuntu.com_ubuntu_dists_xenial_InRelease into data and signature failed
  Clearsigned file isn't valid, got 'NODATA' (does the network require authentication?)
Get:6 http://fi.archive.ubuntu.com/ubuntu xenial-updates InRelease [102 kB]
Err:6 http://fi.archive.ubuntu.com/ubuntu xenial-updates InReleaser/lib/apt/lists/partial/fi.archive.ubuntu.com_ubuntu_dists_xenial-updates_InRelease into data and signature failed
  Clearsigned file isn't valid, got 'NODATA' (does the network require authentication?)
Get:7 http://fi.archive.ubuntu.com/ubuntu xenial-backports InRelease [102 kB]
Err:7 http://fi.archive.ubuntu.com/ubuntu xenial-backports InReleasefi.archive.ubuntu.com_ubuntu_dists_xenial-backports_InRelease into data and signature failed
  Clearsigned file isn't valid, got 'NODATA' (does the network require authentication?)
Reading package lists... Done
E: GPG error: http://mirror.netinch.com/pub/mariadb/repo/10.1/ubuntu xenial InRelease: Clearsigned file isn't valid, got 'NODATA' (does the network require authentication?)
E: GPG error: http://ppa.launchpad.net/ondrej/php/ubuntu xenial InRelease: Clearsigned file isn't valid, got 'NODATA' (does the network require authentication?)
E: GPG error: http://security.ubuntu.com/ubuntu xenial-security InRelease: Clearsigned file isn't valid, got 'NODATA' (does the network require authentication?)
E: GPG error: http://security.ubuntu.com/ubuntu xenial InRelease: Clearsigned file isn't valid, got 'NODATA' (does the network require authentication?)
E: GPG error: http://fi.archive.ubuntu.com/ubuntu xenial InRelease: Clearsigned file isn't valid, got 'NODATA' (does the network require authentication?)
E: GPG error: http://fi.archive.ubuntu.com/ubuntu xenial-updates InRelease: Clearsigned file isn't valid, got 'NODATA' (does the network require authentication?)
E: GPG error: http://fi.archive.ubuntu.com/ubuntu xenial-backports InRelease: Clearsigned file isn't valid, got 'NODATA' (does the network require authentication?)

在此之后，我一直在寻找解决方案，但是没有一个建议的解决方案起作用。

服务器不使用代理（ISP也不使用），因此这不是代理问题。

我已经尝试了很多建议的解决方案，以至于老实说，我什至都不记得我已经尝试过的所有内容，但至少记住以下几点：

• apt clean-> apt update =相同的最终结果（apt clean成功）
• 手动删除/ var / lib / apt / lists和/ var / lib / lists / partial
• 使用https://repogen.simplylinux.ch/重新创建了/etc/apt/sources.list
• 手动创建的/etc/apt/trusted.gpg.d/文件
• 尝试使用其他国家/地区的回购

该服务器是一台独立的计算机，不是通过LAN连接的VM（不能是WiFI或移动宽带问题）

该服务器仅具有Samba，OpenVPN（强制性）以及用于内部测试的apache，php和mariadb（可选）。

因此，有什么方法可以将所有与“ apt-get”相关的内容“默认”起来，以便进行更新？

目前服务器已启动并正在运行（一切正常），因此这并不重要，但是我希望服务器保持最新状态，因为它已连接到Internet。

由于这是服务器，因此我无权访问任何GUI工具。（仅通过ssh访问）

请不要自动将其标记为重复项，因为我想我已经在该站点上尝试了所有类似的问题解决方案。