E: Unable to locate package xxx appears when installing software on Ubuntu

Problem Description:

I recently purchased an Alibaba Cloud ECS server, which is configured with a Liunx Ubuntu system. Some software needs to be installed during use, but the installation fails: "E: Unable to locate package XXX" (Unable to locate package XXX, that is, the software source cannot be found).

Solution:

After many attempts and reading the information, it is found that the software warehouse has not been updated . After the update, it can be installed normally. The operation is as follows:

sudo apt update

sudo apt upgrade

sudo apt install -f