Xshell connect not upstream Linux system

Had appeared before. The host on my Linux system can ping a computer in Windows, and Windows can ping the Linux through. But Xshell cannot connect.

First, I feel like it's not me. The port of the Linux system was shut down by the firewall.

Executed the code: sudo UFW status to view the status,

Then it felt like there was no shell server installed,

To install the SSH service, enter the command: #sudo apt-get install Openssh-server

Start Service: #/etc/init.d/ssh start

Whether the native test is able to log on successfully: #ssh-L user name native IP

Xshell connect not upstream Linux system