After logging in, enter the following command:

CentOS:

yum install ca-certificates wget -y && update-ca-trust force-enable

Debian/Ubuntu:

apt-get install ca-certificates wget -y && update-ca-certificates

Then you can start the installation.

Do not uninstall kernel version (recommended):

wget -O tcpx.sh "https://git.io/JYxKU" && chmod +x tcpx.sh && ./tcpx.sh

Uninstall kernel version:

wget -O tcp.sh "https://git.io/coolspeeda" && chmod +x tcp.sh && ./tcp.sh

After pressing Enter, we can see the following interface.