Error "fatal: Could not read from remote repository." when trying to clone a github repository

Nice to meet you.
I have posted a question on teratail, but I have not been able to get an answer, so I would like to ask for your cooperation.
When I try to clone the github repository, I get an error of "fatal: Could not read from remote repository."

There is no problem if you answer either here or teratail.

Purpose
·I want to publish what I developed in Ravel on xserver

Current State
·I am trying to clone the repository in github with the ssh connection to the xserver, but the error cannot be resolved

What I would like to ask you
·Please tell me how to solve the error when I try to clone it

Tried
·$evalssh-agent
·ssh-T [email protected]

Simply put, this is the situation.

If you need any other information, please let me know.
Thank you for your cooperation.