Network settings look ok.
It appears there had been some issue last year with older versions of Plex for Android / PMS where the client misinterpreted the actual settings. What versions of Plex Media Server and Plex for Android (TV) are you running in that setup of yours?
Is the Plex app on your Android TV signed in to your account or did you configure this a pure local connection (specifying the PMS’ local IP)?
DLNA
Why the DLNA settings… I thought you’re using the Plex for Android app?
If you’re trying to use Plex via DLNA, that Android Box parameter in the DLNA client preferences might cause some trouble… there used to be a pretty technical string, e.g.
IP=<PMS_IP_address>,DirectPlay=true,DirectStream=true,LocalResolution=1920x1080,RemoteResolution=1280x720,OnlineResolution=1280x720,LocalVideoQuality=74,RemoteVideoQuality=49,OnlineVideoQuality=49,SubtitleSize=100,AudioBoost=100,MusicBitrate=192
This string is usually automatically generated and should not be meddled with unless you’re familiar with DLNA parameters 
Warning! : Even more so than with most other “Advanced” settings, you should be very careful about altering settings here. You should do so only if instructed to do so or if you know specifically why you’re making a change and exactly what the appropriate value for the setting is.
