I found the issue today and thought it should be reported as below. Thanks.
$ ruby-whois google.cm
Your request could not be performed.
ylee@bt:/mnt/hgfs/liy4/Barclays/BESTwebDiscovery$ whois google.cm
This TLD has no whois server, but you can access the whois database at
The issue was fixed in e46cb6e. Actually, after this fix, this library is more up-to-date compared to the whois binary because the binary still assumes the domain has not whois server (while it does).
The fix is already available, but it will be included in the next major release.
Nice. Thank you for the link.