我在 Debian 8 服务器 8.11 上安装 nginx-extras 时遇到问题。'apt-get install nginx-extras' 返回：
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
nginx-extras : Depends: nginx-common (= 1.6.2-5+deb8u6) but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
安装的nginx版本是：1.15.12 在apt sources.list下面：
deb http://ftp.nl.debian.org/debian/ jessie main
deb-src http://ftp.nl.debian.org/debian/ jessie main
deb http://ftp.nl.debian.org/debian/ jessie-updates main
deb-src http://ftp.nl.debian.org/debian/ jessie-updates main
deb http://security.debian.org/ jessie/updates main contrib
deb-src http://security.debian.org/ jessie/updates main contrib
deb http://nginx.org/packages/mainline/debian/ jessie nginx
deb-src http://nginx.org/packages/mainline/debian/ jessie nginx
知道如何解决这个问题吗？