If you see this error when using any of our software (or other software that requires internet connectivity) it normally means one thing... You haven't set up your IBM i networking properly. More specifically, you haven't specified DNS servers that are used to resolve a host or domain name to an IP address in the outside work (ie, the internet, interweb, etc...)
When making a request to a host name, such as google.com, your system needs to look up the IP address of that host name to know where to connect to. It would be similar if you told your friend to call John Smith. Without a phone book, he wouldn't know what number to call to contact John. So you can think of DNS servers as a phone book for the internet.
In order to let your IBM i find the IP addresses of host numbers you should specify the DNS Server(s) in the Configure TCP/IP (CFGTCP) command, option 12. You can also get there using the Change TCP/IP Domain (CHGTCPDMN) command.
Once there you will see an place to enter one or more DNS servers:
Change TCP/IP Domain (CHGTCPDMN) Type choices, press Enter. Domain name server: Internet address . . . . . . . '126.96.36.199' Internet address . . . . . . . '188.8.131.52' Internet address . . . . . . . *SAME
In this instance I have specified to use Google's public DNS servers, but in your instance you will want to contact your Network Administrator to find out what values to use here.
Now, you may be tempted to simply use PING on your PC to resolve a host or domain name to an IP address and simply use that on GETURI, MAILTOOL, or another command asking for an internet address or host name. DO NOT DO THIS. The same goes for adding your own entries in a Host Table Entry. This should almost NEVER be done, especially in production. The proper use of DNS servers is important. See this article for more information on that.
As always, feel free to contact us with any questions.