If you have recently transferred your Funimation app from PS4 to PS5, you may receive the following message: "This app is playable only on PS4."
This is because the Funimation app for PS4 and the Funimation app for PS5 are two separate applications. To fix this issue, please delete the Funimation app from your PS5 and then go to the media tab/ all apps on your PS5 console and download the Funimation application again. Once this is downloaded the message should no longer appear and you'll be ready to go!