Mark,
Yes, I have looked at your debug files.
I confirmed your Remote Access is not open
Nov 12, 2023 16:09:09.840 [140195900160824] DEBUG - [EventSourceClient/pubsub/192.46.236.7:443] PubSub: Got notified of reachability for async identifier cf91fd66-c89d-4d64-9e50-306a05a821b9: 0
(0 = NO, 1 = YES)
In looking at your logs, I see you start playback then stop / disconnect ?
Plex Media Server.log:Nov 12, 2023 20:24:40.119 [139970824170296] DEBUG - handleStreamRead code 104: Connection reset by peer
Plex Media Server.log:Nov 12, 2023 20:25:28.664 [139970824170296] DEBUG - Failed to stream media, client probably disconnected after 16547840 bytes: 104 - Connection reset by peer
Plex Media Server.log:Nov 12, 2023 20:25:28.730 [139970822060856] DEBUG - Failed to stream media, client probably disconnected after 16678912 bytes: 104 - Connection reset by peer
Plex Media Server.log:Nov 12, 2023 20:25:28.867 [139970824170296] DEBUG - Failed to stream media, client probably disconnected after 16613376 bytes: 104 - Connection reset by peer
Plex Media Server.log:Nov 12, 2023 20:25:29.063 [139970824170296] DEBUG - Failed to stream media, client probably disconnected after 16695296 bytes: 104 - Connection reset by peer
Plex Media Server.log:Nov 12, 2023 20:25:35.076 [139970824170296] DEBUG - Failed to stream media, client probably disconnected after 133464064 bytes: 104 - Connection reset by peer
Plex Media Server.log:Nov 12, 2023 20:25:41.673 [139970822060856] DEBUG - Failed to stream media, client probably disconnected after 16515072 bytes: 104 - Connection reset by peer
Plex Media Server.log:Nov 12, 2023 20:26:42.283 [139970824170296] DEBUG - Failed to stream media, client probably disconnected after 208257024 bytes: 104 - Connection reset by peer
How is your QNAP connected to the internet?
Is the default gateway address correctly pointing at your modem/router IP?
As comparison, When I disable port forwarding for my QNAP, I get the same error as you
Nov 12, 2023 20:33:58.932 [547503436000] DEBUG - [HttpClient/HCl#16] HTTP/2.0 (0.2s) 422 response from POST https://plex.tv/servers.xml?auth_token=xxxxxxxxxxxxxxxxxxxx (reused)
Nov 12, 2023 20:33:58.932 [547438862560] DEBUG - MyPlex: Published Mapping State response was 422
Nov 12, 2023 20:33:58.932 [547438862560] DEBUG - MyPlex: Got response for 2ef482668a07558d21ed9776082edae8110368a6 ~ registered :0
Nov 12, 2023 20:33:58.932 [547438862560] DEBUG - MyPlex: updating mapped state - current state: ‘Unknown’
How do you have the network defined on your machine?
Question: Have you tried accessing your server in your mobile browser using https://app.plex.tv on the LAN WiFi ?