I have my Roku+ attached to my older tv with composite connectors. I have always been able to connect to Prime Video this way. In the last couple of days, I can't seem to get Prime Video to work. Netflix, Disney and Hulu work just fine. Any clue as to why I can't connect to Prime Video? I replaced my old Roku+ with another of the same model and have the same problem. I tried the Roku+ on another tv and had the same problem. I have other models of Roku on other tv's and have no problem accessing Prime Video on them. All of the others are connected by HDMI. Is it possible that Prime Video won't work on a composite connection anymore? Stumped.
Just so we can assist better, saying Roku+ isn't enough of a player model. There are numerous players that have + in the name. I realize you are referring to an Express +, but even so there are two versions: model 3710 and 3910. Sometimes it's important to know exactly which model it is.
Dan Roku Stick (3600), Ultra (4640), Ultra (4670), 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.