I am experiencing the same issue when attempting to play content on Plex PS4 via Alexa. Plex is working fine on my PS4 otherwise.
Alexa is able to identify and set the PS4 Plex player, and can suggest titles or describe what is on deck. When I try to play a video, I get the following message: “Uh oh! Something weird just happened. Alarm bells are ringing around the world as Plex engineers are rushing to fix this issue.”
I am able to play Plex video content using Alexa on my Windows browsers, as well as using my native LG TV Plex App. I suspect this issue is specific to the PS4 implementation.
Has anyone else noticed this issue, or found a way to fix it?