WD My Cloud Home running PMS 1.43.0.10492. Remote access only works through Relay. Port 32400 was verified with tcpdump. Logs repeatedly show “SSL certificate problem: unable to get local issuer certificate” and “[CERT/OCSP] getCertInfo failed.” Please check and reset/revoke my server certificate.
192.168.0.206 is the client computer accessing Plex Web. The My Cloud Home/PMS is still 192.168.0.160. Tcpdump confirmed WAN traffic is translated to 192.168.0.160:32400 and the server replies. The port forward is correct. The remaining repeated error is “unable to get local issuer certificate” for plex.direct.
You do have some CERT weirdness going on but not the 429 rate limit error.
DNS doesn’t resolve against your plex.direct address and you have error 60.
cURL error 60 is an SSL certificate verification failure where cURL cannot verify the remote server’s identity against local Certificate Authority (CA) certificates. This typically occurs due to outdated CA bundles, self-signed certificates, expired certificates, or corporate proxy interference.
Other than checking the time on your devices and fixing your DNS I have no other suggestions.
OpenSSL confirms the certificate is valid and issued by YR2, but PMS serves only 2 certificate blocks. Verification returns error 20. The correct chain should be EE → YR2 → Root YR → ISRG Root X1, so the cross-signed Root YR intermediate appears missing. Since this is My Cloud Home, I cannot manually replace the certificate bundle. Please reset/reissue it with the complete chain.
My Android phone can reach the server directly on cellular by opening http://172.249.238.22:32400/identity. It returns the Plex MediaContainer XML with the correct machineIdentifier.
A TV on a different network also plays Direct Play remotely.
So the server and port forward are reachable. The problem appears to be Plex app discovery/certificate validation. The Android app still shows the server offline while direct HTTP access works.
Since you believe it is a CERT issue:
Stop Plex
Find your cert-v2.p12 file, rename or remove. Somewhere in the path ~/Library/Application Support/Plex Media Server/Cache
Start Plex and wait for a new one to be downloaded.
Let’s Encrypt has a rate limit so I would not do this repeatedly.