Hello, after migrating from 3 to 4 i get

Incomplete response received from application

This is what i have in the log

App 21094 stderr: [ 2015-04-09 13:58:03.2166 21152/0x00000001959538(Worker 1) utils.rb:85 ]: *** Exception ThreadError in Rack application object (deadlock; recursive locking) (process 21152, thread 0x00000001959538(Worker 1)):
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/gems/rack-1.4.5/lib/rack/lock.rb:14:in `lock'
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/gems/rack-1.4.5/lib/rack/lock.rb:14:in `call'
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/gems/rack-cache-1.2/lib/rack/cache/context.rb:136:in `forward'
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/gems/rack-cache-1.2/lib/rack/cache/context.rb:245:in `fetch'
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/gems/rack-cache-1.2/lib/rack/cache/context.rb:185:in `lookup'
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/gems/rack-cache-1.2/lib/rack/cache/context.rb:66:in `call!'
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/gems/rack-cache-1.2/lib/rack/cache/context.rb:51:in `call'
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/gems/railties-3.2.21/lib/rails/engine.rb:484:in `call'
[ 2015-04-09 13:58:03.2167 21062/7f09e27a5700 age/Hel/Req/Utils.cpp:89 ]: [Client 7-1] Sending 502 response: application did not send a complete response
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/gems/railties-3.2.21/lib/rails/application.rb:231:in `call'
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/gems/railties-3.2.21/lib/rails/railtie/configurable.rb:30:in `method_missing'
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/bundler/gems/rack-protection-5a7d1bd2f05c/lib/rack/protection/frame_options.rb:31:in `call'
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/bundler/gems/rack-protection-5a7d1bd2f05c/lib/rack/protection/json_csrf.rb:18:in `call'
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/gems/rack-1.4.5/lib/rack/builder.rb:134:in `call'
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/gems/rack-1.4.5/lib/rack/urlmap.rb:64:in `block in call'
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/gems/rack-1.4.5/lib/rack/urlmap.rb:49:in `each'
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/gems/rack-1.4.5/lib/rack/urlmap.rb:49:in `call'
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/gems/passenger-5.0.6/lib/phusion_passenger/rack/thread_handler_extension.rb:85:in `process_request'
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/gems/passenger-5.0.6/lib/phusion_passenger/request_handler/thread_handler.rb:149:in `accept_and_process_next_request'
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/gems/passenger-5.0.6/lib/phusion_passenger/request_handler/thread_handler.rb:110:in `main_loop'
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/gems/passenger-5.0.6/lib/phusion_passenger/request_handler.rb:414:in `block (3 levels) in start_threads'
App 21094 stderr:       from /home/openproject/.rvm/gems/ruby-2.1.3/gems/passenger-5.0.6/lib/phusion_passenger/utils.rb:111:in `block in create_thread_and_abort_on_exception'