Hi centa. Welcome to LinuxQuestions.org!
I think that your commands look OK. Maybe you only experienced a little Internet hickup? If you issue this command:
do you get an IP address or an error message?
I just tried it here and I got the address. By the way, in case you don't know, nslookup makes a DNS (Domain Names System) lookup to translate an alphabetical web address to an IP address. You could also try
to see the IP address of this site.
This kind of problems occur sometimes if your Internet provider's DNS server is not fully updated. If you get it a lot, then you should contact your ISP about it.