WD MyPassport Wireless Pro

I installed PLEX on the drive, added my media to PLEX and then hit a road block.
Certain videos give me the “This server is not powerful enough to convert video” error. Some work. most dont. I set the video remote quality to original thinking it will stop trying to transcode it. any suggestions?

Any way to force Direct play or Direct Stream? so i dont get the "This server is not powerful enough to convert video"message?

hmmm changed server to Twonky and using Infuse app and suddenly it works perfectly on my IOS Device… including MKV movies… what are the optimum settings for PLEX to work?

What is the device and what type of files are not playing?
If your device can’t natively play the file then Plex has to transcode and the Wireless Pro cannot do that (not strong enough as you have learned).
Or, conversely, if it needed to download a codec to play the file and you weren’t connected to the internet the same thing would happen.

Some entries from the Support Page:

Do I need to be connected to the Internet to use this device?
For standard use, the device will not need an internet connection when playing content on a Plex app. There are some situations where internet access is necessary:
When you add content to your library, as the server gathers metadata for your media
An internet connection may also be necessary the first time you play media, as the server may need to download certain system components
If you use Plex Home and want to fast user switch to a different member of your Home
Can the My Passport Wireless Pro transcode video?
The My Passport Wireless Pro does not support transcoding of video. To get the most out of it, you will want to use media that has already been optimized and can be Direct Played by the Plex apps you’ll be using for playback.
What if my media is not natively compatible?
If your media is not already natively compatible, you’ll likely want to convert things beforehand. You could, of course, use a third-party tool to re-encode content.
However, if you have Plex Media Server running on your computer, you can also make use of our Media Optimizer feature to prepare content. You could create optimized versions and then copy those over to the My Passport Wireless Pro yourself.
Alternatively, you could point the optimization output location to a folder located on your Wireless Pro, which you could then use as a source location for a local library.

https://support.plex.tv/hc/en-us/articles/221104248-Western-Digital-My-Passport-Wireless-Pro