Roku doesn't offer technical support via this forum. There are two Roku employee moderators that do their best to assist, but they are not tech support.
Can you be more specific? Is it the network connection that is intermittent, or does the picture and/or audio cut out? Does the image freeze, or does the screen go black?
Dan Roku Stick (3600), Ultra (4640), Ultra (4670), Ultra (4800), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.