Set Settings > Remote Access > Manually Specify public port to 443
Set Settings > Network > Custom server access URLs to https://plex.jafner.net:443 The settings page may incorrectly report that the server is inaccessible.

LG WebOS TV Video Format Support

From LG's documentation:

Fixing Plex Exporter

When Plex is restarted you will likely need to give the exporter a new Plex token so it can connect to Plex.

Open Plex.
Log into any account.
Select a locally-hosted piece of media (any media). Open the information page for that media, you do not need to play it.
From the triple-dot menu for the media, click "Get Info" to open the Media Info panel.
At the bottom right of the Media Info panel, click "View XML".
The Plex token is contained in the URL for the XML page. It should be at the very end of the URL, and look like X-Plex-Token=4eBmSrpfXxxgT3cRF2gC. The token is the part after the =.
Copy that value. Paste it into the configuration for "--token=<token-goes-here>" under the command: section of the docker-compose.yml
Sync the changes via git.
Restart Plex exporter with docker-compose up -d --force-recreate exporter-plex