I had many, many problems with my Infuse on Apple TV using an external drive on my iMac for the videos. Also had troubles with my music library with my Sonos speakers. I got an error when I tried to use SMB and I got frequent whirly bird video drop outs.
Well both were solved. I had been using both ethernet and Wifi on my Mac to the same network (it takes ethernet as first priority and then WiFi.
Recently, I got the latest Google/Nest Wifi pucks and the WiFi is so good, I am phasing out ethernet. When I switched to WiFi only on the Mac, I could once again use SMB on Infuse (I had to delete the previous Shares and start over). My Sonos libraries worked again.
And fast, fast videos with no dropouts. Although using both ethernet and WiFi is allowed on a Mac, I won’t do that again.