Again, "The operation failed. Please log in to DSM again and retry."

General Discussions
2

The behavior here is well defined and has already been addressed.

If you installed PlexMediaServer 1.24.2.4973 or higher -

  1. You have a PlexMediaServer shared folder
  2. The contents of your Plex share will be empty and now located in the new shared folder.

Migration did continue to run after DSM issued the timeout – even if you logged out.

The only way to fracture migration is to reboot the NAS.