I searched for a domain name it found already registered but when I searched it in who.is no result found
Whois Error: No Match for "xxxxxxxxxxx.COM" Information Updated: 2017-05-09 04:01:35
Is it possible to buy this domain name?
Use the relevant registry whois server (either CLI or website). If this is really a
.COM see https://www.iana.org/domains/root/db/com.html for which whois server to query and website to visit.
If you use any other tool than the registry provided one, you expose yourself to partial/delayed/wrong results and/or surveillance and logging of your queries.