ssh_exchange_identification: Connection closed by remote host

hi
i am trying to connect the frontend server using ssh
i got the following error

ssh_exchange_identification: Connection closed by remote host
can anyone help please

This thread doesn't have to be in the Programming I guess, but still :
There may be few reasons why you're getting this message, some of them :
Check /etc/hosts.allow and /etc/hosts.deny;
Check the server logs, both remote and local;
Check the way ssh server is configured : look for file sshd_config;
Ask the local server administrator, if that's not you, whether he has had introduced new changes to the servers' policies.