I used a different phone that also used android to connect to chromecast and when that stopped working yesterday, I started to look for more general solutions.
According to this post: Plex Android App don't find cast devices
Enabling config.claspws.tv in domain in Pihole solved that users issue. I tried it and it worked for me as well.
I want to emphasize that I am very disappointed with the rollout of this app and with Plex’s communication throughout the process.
