Connection to github.com closed by remote host.

En el archvo .config/ssh agregamos:

Host *
  ServerAliveInterval 60
  ServerAliveCountMax 60

Host *.github.com
    StrictHostKeyChecking yes
    IdentityFile ~/.ssh/github
    ServerAliveInterval 60
    ServerAliveCountMax 60

Esto permitirá 60 minutos de conexión.

Está causado porque se agotá el tiempo de espera de la conexión SSH.

Fuente: https://stackoverflow.com/questions/60833006/connection-to-github-com-closed-by-remote-host-when-pushing

I can’t explain the long hang time, but the eventual Connection to github.com closed by remote host message is likely caused by your SSH connection with GitHub timing out. I recently helped a coworker solve a similar issue where our Husky pre-push hook was taking a long time to complete on her machine. By the time the hook finished, she received the same Connection to github.com closed by remote host message.

We found the solution was keeping her connection alive by setting values for ServerAliveInterval and ServerAliveCountMax in her .ssh/config file. For example, adding the following settings would send a null packet to the server every 60 seconds (keeping the connection alive) for 30 rounds. This would buy you 30 minutes of connection.

Host *
  ServerAliveInterval 60
  ServerAliveCountMax 30

You can adjust the the values however you see fit for your use.