Remote access has stopped working.

Hi. I recently set up Plex Media Server on a QNAP 453 Pro everything was working well until I had to shut down my device and move it to a different room. When I turned it back on remote access stopped working, I've since moved it back but I can't get remote access working again. I have the latest version of Plex, I tried restarting my router, temporarily disabling firewalls, turning off my VPN (even though it was working before with it running).
Under server mapping in settings I have the green arrow between public and private but the red X between Internet and Public.
I've tried setting up a static IP on my Mac but had little success.
Does anyone have any suggestions? Any help is appreciated. Thanks.