Push to Heroku fails: Could not find net-ssh-2.10.0 in any of the sources. Failed to install gems via Bundler

Question

I tried pushing my app to heroku but get the following error:

remote: -----> Using Ruby version: ruby-2.2.2
remote: -----> Installing dependencies using 1.9.7
remote:        Running: bundle install --without development:test --path vendor/bundle --binstubs vendor/bundle/bin -j4 --deployment
remote:        Fetching gem metadata from https://rubygems.org/...........
remote:        Fetching version metadata from https://rubygems.org/...
remote:        Fetching dependency metadata from https://rubygems.org/..
remote:        Could not find net-ssh-2.10.0 in any of the sources
remote:        Bundler Output: Fetching gem metadata from https://rubygems.org/...........
remote:        Fetching version metadata from https://rubygems.org/...
remote:        Fetching dependency metadata from https://rubygems.org/..
remote:        Could not find net-ssh-2.10.0 in any of the sources
remote:  !     Failed to install gems via Bundler.
remote:  !     Push rejected, failed to compile Ruby app

What can I do about this?

I've removed Gemfile.lock to see if rebuilding this file would make a difference, but it didn't. Also, I've tried gem uninstall net-ssh-2.10.0 and then bundle install before pushing to heroku. Also, I removed fog from my Gemfile since that's the gem with which net-ssh-2.10.0 comes along; then did bundle update, gem cleanup, put fog back in the Gemfile, ran bundle install, pushed to git, and pushed to heroku with again the same result.

My Gemfile:

source 'https://rubygems.org'

ruby                  '2.2.2'
gem 'rails',          '4.2.3'
gem 'bcrypt',         '3.1.10'
gem 'faker',          '1.4.3'
gem 'carrierwave',    '0.10.0'
gem 'mini_magick',    '4.2.9'
gem 'fog',            '1.32.0'
gem 'aws-sdk',        '2.1.11'
gem 'sass-rails',     '5.0.3'
gem 'bootstrap-sass', '3.3.5.1'
gem 'uglifier',       '2.7.1'
gem 'coffee-rails',   '4.1.0'
gem 'wice_grid',      '3.5.0'
gem 'bootstrap-datepicker-rails', '1.4.0'
gem 'friendly_id',    '5.1.0'
gem 'jquery-rails',   '4.0.4'
gem 'turbolinks',     '2.5.3'
gem 'jbuilder',       '2.3.1'
gem 'sdoc',           '0.4.1', group: :doc
gem 'pg',             '0.18.2'

group :production do
  gem 'rails_12factor',     '0.0.3'
  gem 'puma',               '2.11.2'
end

Answer 1

It seems that this version just has been removed from Rubygems... May we have to do a downgrade or an upgrade...

The cause of deletion is here.