We used Will’s YouTube video to set up Plex our main NAS. Everything worked nicely. We followed the steps here Plex/Synology - Custom domain with HTTPS - Imgur to add the same cert the NAS is using and everything worked nicely, again. Needless to say we have NO experience with Plex at all.
We had some general questions about Plex, and we posted in their forums. Someone pointed out to the Plex version being old. Before doing anything stupid, we contacted Synology support to ask for the correct way of updating Plex and they told us to use Plex’s packages.
So, we did download v 1.41.0.8994 for DSM 7 (we are running DSM 7.2.1-69057 Updates 5 over a DS1621+).
We applied the update while logged to the NAS in the LAN but NOT via its local IP but its FQDN. After the update, HTTPS access to the NAS from the outside fails with the “connection isn’t private” message. We have done everything, re-generated the PK12 certificate, uploaded to Plex, stop, start and we have even set false data in the “Custom certificate location” … it’s like Plex can’t use the cert. Reading all over the place, we found out that OpenSSL used in the article above was old, so we followed this article to get OpenSSL v3.3.2.
Meanwhile, we created a post in Plex forums, and a good guy is trying to help but a pace that it is to slow for our needs. I was lucky to find somewhere in the Plex logs a line with this: ERROR - CERT: Found a user-provided certificate, but couldn’t install it.
Nothing that we do fixes the problem and the PFX certificate is find, we can import it into any certificate local stores and shows correctly.
We are at the point of uninstalling Plex and start all over again but, as novices, we do not know what needs to be closed/cancelled on Plex’s side.
Our only theory is that by applying the Plex update by accessing the NAS via its FQDN instead of its LAN IP, we broke something.
Any light anyone can shed will be appreciated.