Plex live tv playback

I have installed plex media server on my raspberry pi 3 b when I play live tv on my fire tv plex client it give me message that the server is not powerful enough to handle it but when I run same live tv on my iPad Pro plex client it runs smooth any explanation or suggestion about this?

It’s related to video transcoding. Your FireTV client asks your Plex server on the pi 3 to transcode the video. Your iPad Pro is able to play the content without video conversion. The pi 3 has not the required computational power to do the transcoding. Try to tweak the Plex player settings on your FireTV or try Kodi with the Plex plugin.

Thank you for your answer I will try your recommendations.