PMS 1.43.x on :32400 accepts, reads, and silently closes every non-TLS
connection from a non-loopback source (loopback exempt). The plain-HTTP
reverse_proxy therefore got EOF and Caddy answered an empty-body 502.
Both Plex vhosts now dial the upstream over TLS with
insecure_skip_verify (PMS self-signed cert, pinned LAN hop only;
client-facing Let's Encrypt TLS unchanged).
Frank
aa473aeddb