Check for DNS rebinding.
See Why Isn’t It Working section of How to Use Secure Server Connections.
Use a public DNS and configure DNSMASQ in DD-WRT advanced settings.
The Ethernet port on the TV is 100 Mbps. Some media, such as 4K HDR BD rips, may burst above that speed. If so, you may experience buffering.
The TV’s WiFi is 802.11ac and capable of speeds faster than 100 Mbps. If you experience buffering with high bit-rate media, try connecting the TV to a 5 GHz Wi-Fi channel.
Is the server on the 192.168.1.0 network? If so, this setting is not necessary and should be removed.
While necessary to use Plex Media Server during an Internet outage, be aware of the implications.
This allows all devices on the 192.168.1.0 network to access the server without authorization. This means all clients have admin rights, including the capability to change server settings and delete media (Plex Web & Desktop). Additionally, there is no enforcement of age related or other such restrictions (if you’ve kids with restricted profiles, they can see all media).
This should not be necessary.
