ssh problem

I downgraded one of my computers to 15.2 because this is the only way to have a sound. After my NFS server problem has been solved now, I have one more problem, i.e. I cannot access to this computer, called "pachew", by ssh.  When ssh is invoked from outside, no prompt for a password appears, but any connection is immediately refused, and this error message appears:        "ssh: connect to host pachew port 22: No route to host" Any suggestions? Thanks in advance, Wolfgang