The problem

If you're experiencing that your bundle install command fails with an error message like this, rubygems.org might have issues with their ipv6 connectivity:

$ bundle install
Fetching source index from https://rubygems.org/

Retrying fetcher due to error (2/4): Bundler::HTTPError Could not fetch specs from https://rubygems.org/ due to underlying error <timed out (https://rubygems.org/specs.4.8.gz)>

The (a little bit dirty) possible solution

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Read more Show archive.org snapshot

If that's actually the case, then you can try to deprioritize the ipv6 connection to the rubygems server, as described here Show archive.org snapshot .

To do so, simply add "precedence 2a04:4e42::0/32 5" to the bottom of your /etc/gai.conf file, and retry bundle install. Maybe the command will succeed now.

Warning

Don't forget to remove the line from the /etc/gai.conf file as soon as you don't need it anymore, so you don't have weird config laying around!