Cannot start Plex from Synology NAS

Good Afternoon, I’m having a real problem trying to get Plex to start with my Synology DS223+ NAS. So far, I’ve reset my router provided by YouFibre, back to factory settings, by pressing restart with a pin,bought back the NAS back to factory settings, and even wiped the two drives in the NAS and created a new volume. The issue is this: I install Plex from the DSM, and allow my folder where the movies are, and the Plex media server folder Full read and write, in both local users and system internal user. When I click “open” on the Plex icon in the DSM, all I get is a black web screen and “loading”… nothing else happens… Could it be a firewall issue? I’ve switched off my Windows firewall off as a temp measure, and the firewall on the NAS as well, plus the firewall on the router. I’m at a complete loss as to what the issue is, and I’ve tried over and over again without success. Any Ideas? Thank you.

Not sure if it’s related, but two other folks posted on Reddit recently in the Plex sub with issues connecting to their local plex instance with YouFibre and the Sagecomm router. There is also a thread on the YouFibre sub about it with several others experiencing the same. It appears to be something with the Sagecomm router. One comment notes they spoke with the YouFibe support and they acknowledged the issue and sent different router.

https://www.reddit.com/r/youfibre/s/k6rTeZ4WLi

https://www.reddit.com/r/PleX/s/qH3oZSvtd8

https://www.reddit.com/r/PleX/s/olP1qefw3r