The requested URL could not be retrieved

While trying to retrieve the URL: /user/n0m1/

The following error was encountered:

Unable to determine IP address from host name for

The dnsserver returned:

Server Failure: The name server was unable to process this query.

This means that:

 The cache was not able to resolve the hostname presented in the URL. 
 Check if the address is correct. 

Your cache administrator is root.

Generated Mon, 15 Aug 2016 19:04:10 GMT by (squid/2.6.STABLE21)