Currently only i386/amd64 architectures and LTS (from 16.04/Xenial to 24.04/Noble) are supported.

Edit your “/etc/apt/sources.list” with administrator privilege (here is 18.04)

deb https://mirrors.westlake.edu.cn/ubuntu jammy main multiverse restricted universe
deb https://mirrors.westlake.edu.cn/ubuntu jammy-updates main multiverse restricted universe
deb https://mirrors.westlake.edu.cn/ubuntu jammy-security main multiverse restricted universe
deb https://mirrors.westlake.edu.cn/ubuntu jammy-backports main multiverse restricted universe
# Below is not recommended.
# deb https://mirrors.westlake.edu.cn/ubuntu jammy-proposed main multiverse restricted universe