'Checking connection speed' indefinitely when trying to play media

I used to be able to play media located on my WD MyCloud Duo server on my Hisense TV using Plex, but it doesn’t work anymore.

Plex Server Version# (running on WD MyCloud Duo): 1.42.2.10156-f737b826c

Plex Player Version# (running on my Hisense TV): Client Version 5.93.2, Platform Version V0000.09.09A.P0930

Plex Player advanced settings: I tested the following, but none work.

Allow Insecure Connections Prefer Insecure Connections
Always Never
On same network as server Never
Never Never
Always On same network as server
On same network as server On same network as server
Never On same network as server
Always Always
On same network as server Always
Never Always

Media Server Status indicated on Plex Player: Indirect

Connection type indicated on MyCloud: sometimes Relay, sometimes Local

I can browse my media, but when I try to play any, I get a “Checking connection speed” message forever.

Also I’m not sure how I’m supposed to set up ethernet cables. Currently, I have 1 cable connecting the MyCloud to my router, and one connecting my router to the TV.

Grateful for your help!