Indexing not working while using FTP

Hey guys, so I’m fairly new to Infuse and using my HDD as a NAS via my FritzBox!-Router.
I fiddled around with SMB but it was just too slow and I had issues with buffering while watching some shows/movies.

I now switched to local FTP, which works like a charm on my AppleTV, iPhone and iPad. But for some reason I can’t get it working on my MacBook.
I established the FTP-connection via Finder (I can see all my stuff via my MacBook on my NAS) but Infuse just keeps getting the error “couldn’t index MY_NAS_NAME“.

Am I doing sth wrong here? Is there a step I did wrong?
I’ve set up my FTP-connection to be local only (not accessible via Internet), due to me just wanted to stream at home.