Retrieving rubygems-1.8.25

There is no checksum for 'http://production.cf.rubygems.org/rubygems/rubygems-1.8.25.tgz' or 'rubygems-1.8.25.tgz', it's not possible to validate it. If you wish to continue with unverified download add '--verify-downloads 1' after the command.

There has been an error while trying to fetch the source. Halting the installation.

哪位大神碰到过，求解