You are getting this issue due to unknown changes in /etc/ssh/ssh_config file. You can resolve this issue with below steps.
Now you can try to login with SSH and hope you can use it without any issue.
- First you can login into your VPS server with console and execute below command.
Code:
sudo apt-get purge openssh-server
mv /etc/ssh /etc/ssh_old
created new ssh directory in /etc
sudo apt-get install openssh-server
Now you can try to login with SSH and hope you can use it without any issue.