Skipping in-sync xx

[yayaasd]

unhappily I am not really able to use the tool, due to geting this error always on every file:

Starting synchronization of show XY
Starting synchronization of XY Season 1...
Skipping in-sync XY s01e01
Skipping in-sync XY s01e02
Skipping in-sync XY s01e03
Skipping in-sync XY s01e04
Skipping in-sync XY s01e05
Skipping in-sync XY s01e06
Skipping in-sync XY s01e07

the series is available on source AND destination plex server.
any Idea about the problem?

I already checked the filenames - still the same. Alco collections names within Plex are the same..