I have a managed subscription to FRNDLY which I purchase using my Roku. I have FRNDLY install on 6 Roku devices however when I attempt to use the channel on three of them it requires a log in. When I enter my Roku information it fails as I excepted. Why can I get this to work on three devices and not on the additional three. All six devices are Roku Express + devices.
A couple of thoughts:
Check that all your Rokus are on the same account (settings->system->about).
If they are, then you might be running into a limitation of Frndly itself. For example, looking at their webpage, I see they have different plans that support 1, 2, or 4 screens at once. Maybe they also have limits on how many devices can be logged in at once. (Just guessing.)
I will connect with them and see if that is the case. Once I get a response from them I will let update this post