Synology model? The exact model is needed, including any “+,” “play,” etc. Example: The DS218, DS218+, and DS218J all have different CPUs and require different Plex Media Server downloads (ARMv8, Intel x64, ARMv7).
Which file did you download? Provide the full name.
Where did you download the file? From the DSM 7 - Packaging 2.0 - Forum Preview thread or from plex.tv/download?