The GeoDNS is giving out a dead IP to europe but live ones to the US, specifically 199.15.176.188 and 207.171.7.49 - so you can monkey patch your hosts file temporarily until the .eu mirror gets brought back up (it's been reported, but volunteer maintained things ...)
Oh, and we're planning to try using rel=canonical to convince google to actually frigging index metacpan.org instead, since apparently their algorithm isn't able to figure out which site is actually being developed on their own (last time I chatted to him about it, the creator of cpansearch.org is genuinely looking forwards to being able to retire from dealing with it, just obviously there's a lot of work involved in a full cutover)
Please use https://metacpan.org instead. It has been the de-facto module search engine used by the Perl community for the past 10 years at least. Only Google still seems to think that search.cpan.org is a thing.
At the next Perl Toolchain Summit (http://act.qa-hackathon.org/pts2018/) work will be done on metacpan.org, not on search.cpan.org. And this will also include work on the Perl 6 Toolchain, for that matter.
In your case: http://search.mcpan.org/search?query=X11-GUITest