Problem while deploying with capistrano-unicorn


since today I have some issue when I try to stop / start / restart
I can’t understand why but it seems to be mixing my local user and my
server user

on config/unicorn/production.rb I have
user ‘userserver’, ‘userserver’

where ‘userserver’ is the name of the user on server
so when I launch command cap unicorn:restart
I have error u can see here

If I simply change

user ‘userserver’, ‘userserver’


user ‘userlocal’, ‘userlocal’

where ‘userlocal’ is the name of the user my personnal computer, then it
working !

do I do something wrong ? I thought that the user in this file should be
the on server, not on local machine.
moreover it was working fine the 6 last month !