I have 2 roku 3 devices. On 1, when i select prime video it says contacting amazon then comes right back out. Other channels are fine. Prime is ok on other box. It was fine on 7/9. I did power it off for 1 minute, no change.
It is a 4200x with 34 channels. It has a 16 GB microsd card. Software is 9.1.0 bld 4111.
I removed the channel, restarted the roku, and re-installed prime video. Now it works.