Since yesterday I have problems connecting to my server using SSH/SFTP. I can only connect after a restart of my server. When I try to make a connection after a couple of minutes, I can no longer make an SSH connection. I get the error "server unexpectedly closed network connection". SSH connections that are already open stay open. My server has CentOS 6 on it.
Furthermore varnish keeps crashing seemingly randomly, which means my sites get down.
In my SSH error log I get the error:
fatal: setresuid 500: Resource temporarily unavailable pam_unix(sshd:session): session closed for user
Any ideas what the problem may be? Thanks