help please........Close Captioning Doesn't Work on Amazon "Expanse" Season 5
I had captions not appearing in HBO Max once, and rebooting the Roku restored it. You might give that a try.
Just checked - CC/subtitles are working on Season 5 of the Expanse.
Make sure yours arent off by default in Prime: during playback, press up/down, subtitles (icon), then verify they are on (sometimes they turn off).