after apt-get install openproject

@[ 2016-09-22 20:20:14.1012 17494/7fa7cc721700 age/Cor/App/Implementation.cpp:304 ]: Could not spawn process for application /opt/openproject: An error occurred while starting up the preloader.
Error ID: c132e1fc
Error details saved to: /tmp/passenger-error-Ds9i3z.html
Message from application: Your Ruby version is 2.3.1, but your Gemfile specified 2.1.6 (Bundler::RubyVersionMismatch)
/var/lib/gems/2.3.0/gems/bundler-1.13.1/lib/bundler/definition.rb:475:in `validate_ruby!’
/var/lib/gems/2.3.0/gems/bundler-1.13.1/lib/bundler.rb:93:in `setup’
/var/lib/gems/2.3.0/gems/bundler-1.13.1/lib/bundler/setup.rb:20:in `<top (required)>’
/usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require’
/usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require’
/usr/lib/ruby/vendor_ruby/phusion_passenger/loader_shared_helpers.rb:430:in `activate_gem’
/usr/lib/ruby/vendor_ruby/phusion_passenger/loader_shared_helpers.rb:297:in `block in run_load_path_setup_code’
/usr/lib/ruby/vendor_ruby/phusion_passenger/loader_shared_helpers.rb:435:in `running_bundler’
/usr/lib/ruby/vendor_ruby/phusion_passenger/loader_shared_helpers.rb:296:in `run_load_path_setup_code’
/usr/share/passenger/helper-scripts/rack-preloader.rb:100:in `preload_app’
/usr/share/passenger/helper-scripts/rack-preloader.rb:156:in `module:App’
/usr/share/passenger/helper-scripts/rack-preloader.rb:30:in `module:PhusionPassenger’
/usr/share/passenger/helper-scripts/rack-preloader.rb:29:in `

’

[ 2016-09-22 20:20:14.1097 17494/7fa7cd825700 age/Cor/Con/CheckoutSession.cpp:285 ]: [Client 4-1] Cannot checkout session because a spawning error occurred. The identifier of the error is c132e1fc. Please see earlier logs for details about the error.
@

Did you have an existing (manual) installation of openproject before trying to install the package? By the look of it you are using an incorrect ruby version, gems from /var/lib instead of /opt/openproject, and you’re trying to launch it with passenger instead of unicorn. You need to first remove your existing installation (including apache config), and then apt-get install openproject and openproject configure.