failed to run the package service

On a brand new NAS I installed Plex and got a message: “failed to run the package service”.

Notes:

  1. PlexMediaServer-0.9.17.2.2159-2bd156c-neon-armv7.spk is the first and only package that I installed
  2. I followed the instructions on How to add Plex’s package signing public key to Synology NAS Package Center
  3. NAS model: Synology DS416
  4. DSM version: DSM 6.0.1-7393

Thank you,
Andrej