System Error 53 with net time and Unix

I’m trying to point all of my DCs to a Unix time server with tne net time command. I keep getting “system error 53”. I’ve verified I can ping both the server name and IP address. I receive the same error “system error 53” when I try to do a net view \\servername or net view \\IP address. One theory is it may be a permissions issue, since we don’t administer the Unix time server. Kinda’ lost now. Any advice?