I did this command ...
got this response ...
Code
# This is file is generated.
# OMV-Extras repos
#
# OMV-Extras.org
deb https://dl.bintray.com/openmediavault-plugin-developers/erasmus jessie main
# OMV-Extras.org Testing
deb https://dl.bintray.com/openmediavault-plugin-developers/erasmus-testing jessie main
# Plexmediaserver
deb https://dl.bintray.com/openmediavault-plugin-developers/erasmus-plex jessie main
deb https://downloads.plex.tv/repo/deb/ public main
attached is the error message I get when trying to do a update through update management