What does "Too many recursive configuration includes" mean when trying to connect to a ssh server?

The current problem is when I try to connect to a ssh server (from a university I am currently attending) with the following (example) command:

ssh -Y 

Then I get the following error:

Too many recursive configuration includes

Beforehand, I could connect to the server without any problem. However, I tried to enable X11 forwarding to run graphics applications. I did this by using the nano editor:

nano -w /etc/ssh/ssh_config

In the nano editor, I removed "#" from ForwardX11 and also changed "no" to "yes". Afterwards, I saved and closed the nano editor by pressing ctrl + O and ctrl + X respectively. Finally, I tried numerous ways to restart "ssh(d) service" (to be honest, since I am new to nano editor and ubuntu in general, I just followed the different sites that explains how to enable ForwardX11). I have tried using the following commands:

systemctl restart sshd.service
systemctl restart sshd
sudo systemctl restart sshd
sudo systemctl restart ssh
service sshd restart
sudo service ssh restart

When trying to restart sshd (not ssh), I get the following message:

System has not been booted with systemd as init system (PID 1). Can't operate.
Failed to connect to bus: Host is down

This could be a seperate problem not relating to the problem stated in this question. However, I just wanted to tell you what I did before I couldn't connect the university's ssh server anymore.

But after I did everything mentioned above, I couldn't connect to the university's server anymore. Again, the error message I receive is:

Too many recursive configuration includes

What have I done wrong? I suspect I did something wrong in the nano editor.

P.S. My current Ubuntu version is 20.04

1 Answer

I (the asker of this question) confirm that this problem has been solved by the user steeldriver (see comments).

When using the following command to enter nano editor (nano -w /etc/ssh/ssh_config), I presumbably accidently removed the hashtag of the line that says Include /etc/ssh/ssh_config.d/*.conf, since I am new to Linux and the controls of the nano editor.

This (probably) caused the saved file (e.g. copy of the modified /etc.ssh.ssh_config) to try to include itself in /etc/ssh/ssh_config.d/*.conf, which then most likely resulted in the error 'Too many recursive configuration includes'.