Recently I encountered this error:
‘This server is not powerful enough to convert video’ and here is what I found out:
When trying to play the same movie on my PC in Plex it says the server is not powerful enough.
You must have the transcoding option on in the Plex settings on Automatic and Ultra Fast.
Then on the TV app settings set the H264 Maximum Level on Disabled. It should work then
I had this same issue, but it turns out, I only found this by turning off another option to resolve why Plex suddenly started refusing to play most files. The error I was initially getting was, “Playback Error - Please check that the file exists and the necessary drive is mounted.”
Unfortunately for me, I do not seem to recall what the original switch I turned off, but turning off that original switch brought me to YOUR issue.
Fortunately for you, what I decided to turn off, just to reduce the possible number of culprits, turned out was causing the “not powerful enough” issue, or at least, turning off, “Include Cinema Trailers from movies in my library” saving and then trying again solve the last issue I had.
Unlike others, I will tell you where to find this option, rather than have you search all day for it like most of the other commenters here. I found this option under Settings ==> Extras. It was the 1st option … I didn’t have to change the, “Choose Cinema Trailers from …” option at all … just saved the changes and tried playing the film again. This solved it for both my PC AND when playing from my Firestick. Hope this helps …
Update: I found the original switch(es) I changed. I changed them following someone else’s advice here, which was to change 2 switches in “Transcoder” setting as follows:
Transcoder quality - Set to Automatic
Background transcoding x264 preset - Set to Ultra Fast
Again, hope this helps … not only people having issues since the last update, which is when this started happening to me, but also to developers who may be reviewing the posts. Guys, ya broke a few things …
Morning,
So I implemented the suggested changes and also moved my plex library onto another newer secondary hard disk, as I had some concerns that the disk itself might have been causing the issue. I will use it for a week or so and see if this intermittent issues continues, before I keep hunting a ghost.
Thanks for all the help.
Ashley.
Oh my Lord thank you. I JUST updated my Server to a 3600x and 1070ti. I had direct stream working and didn’t really have a problem keeping multiple file types, but after a bunch of research (mostly the one post I call the bible of 4k transcoding… Don’t remember who wrote it, just that it has all the information) it really didn’t seem too crazy to do in 2021…I had the 1070ti laying around from another build so I wanted to try it and couldn’t figure out for the life of me why it wouldn’t work.
I’m glad I could help 
.
