If you obtain error with :
plaster.exceptions.LoaderNotFound: Could not find a matching loader for the scheme "file+ini"".
you most probably don't set correctly TRACIM_CONF_PATH or TRACIM_WEBDAV_CONF_PATH. You have to set a correct absolute path. be careful for uwsgi ini file :
# incorrect
env = TRACIM_CONF_PATH="/home/me/tracim_v2/backend/development.ini"
# correct
env = TRACIM_CONF_PATH=/home/me/tracim_v2/backend/development.ini