ssh: connection refused

I use Terminal to connect to a server without problems. Then some times the connection was refused. Today I can not connect to the server. I tried a lot of things but nothinh works.

This is what I got:

JVMacPro:~ jorgevitor$ ssh xxx.xxx.xx.xxx

ssh: connect to host xxx.xxx.xx.xxx port 22: Connection refused

I was looking at some discussions and one of the informations I got is

JVMacPro:~ jorgevitor$ codesign -vv /usr/bin/ssh-agent

/usr/bin/ssh-agent: valid on disk

/usr/bin/ssh-agent: satisfies its Designated Requirement

In a PC I can login.

What shall I do?