FAQ 28 - DSM Complains Port 32400 In Use When Installing Plex
This error , reported by Package Center, tells you that Plex’s port 32400 is already in use.
The most commonly observed cause of this is having previously installed Plex in Docker but never removing Plex from Docker.
DSM 7 now enforces port usage monitoring and will not allow you to install a program if its main port(s) are in use.
Please open Docker , Check for an old Plex definition / instance, Delete it if no longer in use.
