"The requested URL could not be retrieved" occurs when using the Squid proxy

Problem:
The following error occurred while using the proxy to access the Web site:
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The requested URL could not is retrieved

While trying to retrieve the Url:http://linkhelp.clients.google.com/tbproxy/lh/fixurl?

The following error was encountered:

Unable to determine IP addresses from host name for linkhelp.clients.google.com

The DNSServer returned:

Timeout

This means:

The cache wasn't able to resolve the hostname presented the URL.
Check if the is correct.

Your cache Administrator is root.
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Workaround:
This is due to the DNS configuration problem of the proxy server machine and the proxy server machine cannot find the IP address of the specified URL. Check that the/etc/resolv.conf file is configured correctly, such as incorrectly adding the correct configuration information, such as:
NameServer ###.###.###.###
NameServer ###.###.###.###
You can configure multiple DNS servers.
Restart the Squid service.