Since I reloaded my server (Windows 2012 Essentials) I have been having this issue. Never had the problem before that. The part that I don’t get is that some devices have no issue at all. On the TV in the same room as the router and server I have tried Roku 4, Roku 3 Roku Stream stick all stop playing every few minutes and go to the movie menu clearing the progress. (It’s infuriating) I also have an Amazon Firestick which has the same issue except it at least gives a message that it could not communicate with the media server and lets you retry from where it stopped. I have tried wired and wireless and different stream rates. I read that adding a large amount of media at once (reloading server)… should optimize the database. Did it, no affect.
The thing I don’t get is that another TV in another room using a Roku Stream stick has no issues whatsoever. Additionally an Iphone 6s plus and Galaxy note tablet have the same issue while an Ipad mini and Galaxy S7 have no issues.