ruby on rails - passenger don't run on app path 'Could not find passenger' -

running passenger on app path (e.g /home/my_app/rails) such:

rvmsudo passenger start 

raising error

dependency.rb:247:in `to_specs': not find passenger ...

the problem caused conflict project gems. should run command outside of app, giving passenger app path handle.

cd ~ rvmsudo passenger start my_app/rails