Playback issue over home network

[Lilly Begonia]

I just bought a second Mac Mini, upgraded both to Sierra, and got them talking to each other over the network in order to share 14.2 tb of video files so I could watch my videos in the living room on my new 32 in. monitor, but it's not working out. I've tried 3 versions of VLC now and they all do the same thing during playback, the video stalls and the screen goes gray for a bit over and over. It makes watching my videos unenjoyable.I've used VLC for years now, and it's my favorite player and I don't want to use QuickTime, (yuck!). I'm thinking this has to be a network issue but I'm not sure how. I have the two Macs sharing via both CAT5 ethernet and WiFi, and still my videos stall every few seconds. I'm not a super geek, and don't know where to start fixing this. It seems to work okay with some videos, and not others, and I have no idea why. Until I got the second Mac and networked them together I had no problems and VLC just worked, all the time, every time. If anyone has a clue what's causing this I'd very much appreciate a heads up.

Thank you!