我在debian buster上安装libgnutls28-dev包时遇到问题，apt抛出以下错误：
Reading package lists... Done
Building dependency tree
Reading state information... Done
Suggested packages:
gnutls-bin gnutls-doc
The following NEW packages will be installed:
libgnutls28-dev
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 1,086 kB of archives.
After this operation, 4,417 kB of additional disk space will be used.
Err:1 http://deb.debian.org/debian buster/main amd64 libgnutls28-dev amd64 3.6.7-4
404 Not Found [IP: 151.101.220.204 80]
E: Failed to fetch http://deb.debian.org/debian/pool/main/g/gnutls28/libgnutls28-dev_3.6.7-4_amd64.deb 404 Not Found [IP: 151.101.220.204 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
困扰我的是，该软件包可在http://deb.debian.org/debian/pool/main/g/gnutls28/libgnutls28-dev_3.6.7-4+deb10u2_amd64.deb获得，由于某种原因，apt在寻找libgnutls28-dev_3.6.7-4_amd64.deb而不是libgnutls28-dev_3.6.7-4+deb10u2_amd64.deb。
我尝试使用运行apt install libgnutls28-dev=3.6.7-4+deb10u2的特定版本并获得以下内容：
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Version '3.6.7-4+deb10u2' for 'libgnutls28-dev' was not found
问题是，这是从哪里来的？是apt问题吗？还是gnutls28误导依赖项？还是首先应该有文件libgnutls28-dev_3.6.7-4_amd64.deb？
[编辑]
根据Knud的评论添加：
根据apt，系统是最新的：
apt update
Hit:1 http://deb.debian.org/debian buster InRelease
Hit:2 http://deb.debian.org/debian buster-updates InRelease
Hit:3 http://security.debian.org/debian-security buster/updates InRelease
Hit:4 http://deb.debian.org/debian buster-backports InRelease
Reading package lists... Done
Building dependency tree
Reading state information... Done
All packages are up to date.
我已确认其中一个软件包制造商，可用的版本_3.6.7-4+deb10u2 是最新版本，并且apt应该知道这一点：
apt-cache policy libgnutls28-dev
libgnutls28-dev:
Installed: (none)
Candidate: 3.6.7-4
Version table:
3.6.7-4 500
500 http://deb.debian.org/debian buster/main amd64 Packages
所以这是apt问题。由于某些原因，即使具有超级牛的力量，apt仍处于过时的状态。任何指导将不胜感激。
[在Andreas Metzler的善意指导下，找到了一个解决方案。
镜像显然被过期的包索引卡住了。据我了解，我使用的是deb.debian.org，它会将apt重定向到附近的服务器。我更新了sources.list中的/etc/apt/文件，因此它们现在指向附近的固定服务器，并且一切正常。