Plex can't access ownCloud data directory

Server
1

Background
I have recently upgraded my server hardware and done a fresh install of both oC and Plex.

Issue
Before the upgrade, Plex had access to media stored in oC data directory after adding the plex user to the www-data group. This doesn't seem to do the trick any more.

Question
How can I give Plex access to media stored in oC data directory in a safe way?

Server configuration
Operating system: Debian

2

Moving to the miscellaneous category as this is mostly a linux basic issue rather then one of oC itself.

Plex will have access to the data folder of oC as soon as your user and group setup of your operating system is configured correctly.