ssh not working: Connection closed by remote host

I was using ssh key but one day suddenly it stopped working. This is what I get when I try to clone. Also, there is nothing in the known_hosts file. What do I do?

sarthak@Sarthak:~/.ssh$ git clone :sarthmit/Andrew-Ng-ML-solutions.git Cloning into 'Andrew-Ng-ML-solutions'... ssh_exchange_identification: Connection closed by remote host fatal: Could not read from remote repository. Please make sure you have the correct access rights and the repository exists. sarthak@Sarthak:~/Desktop/Web Scraping$ ssh -vvv OpenSSH_7.2p2 Ubuntu-4ubuntu2.2, OpenSSL 1.0.2g 1 Mar 2016 debug1: Reading configuration data /etc/ssh/ssh_config debug1: /etc/ssh/ssh_config line 19: Applying options for * debug2: resolving "github.com" port 22 debug2: ssh_connect_direct: needpriv 0 debug1: Connecting to github.com [192.30.253.113] port 22. debug1: Connection established. debug1: identity file /home/sarthak/.ssh/id_rsa type 1 debug1: key_load_public: No such file or directory debug1: identity file /home/sarthak/.ssh/id_rsa-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /home/sarthak/.ssh/id_dsa type -1 debug1: key_load_public: No such file or directory debug1: identity file /home/sarthak/.ssh/id_dsa-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /home/sarthak/.ssh/id_ecdsa type -1 debug1: key_load_public: No such file or directory debug1: identity file /home/sarthak/.ssh/id_ecdsa-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /home/sarthak/.ssh/id_ed25519 type -1 debug1: key_load_public: No such file or directory debug1: identity file /home/sarthak/.ssh/id_ed25519-cert type -1 debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.2 debug1: ssh_exchange_identification: debug1: ssh_exchange_identification: debug1: ssh_exchange_identification: Error: Must authenticate before using this service. ssh_exchange_identification: Connection closed by remote host 

3 Answers

debug1: Connecting to github.com [192.30.253.113] port 22. 

That does not look like github IP

debug1: ssh_exchange_identification: Error: Must authenticate before using this service. 

That is not SSH identification string.

You are connecting from behind some proxy/firewall that prevents you from using SSH. You should talk with your network administrator.

Or use HTTPS to clone your github repositories.

I got exactly the same issue.

192.30.253.113 IS a github IP without any problem.

For my case, I have "service filter" rule in my router setting, which disabled port 22 for some reason.

You can try to check your router configurations as well.

Just ran into this problem - Gitlab server was actually down for planned maintenance!

ie: nothing wrong on my client end.