Can't access plex with Browser can with apps in android/roku inside/outside home

Version 1.23.4.4805

I can go to my external IP:Manual port and get to server but it’s unsecure. I can’t access app.plex.tv and get that way to my server. Android/roku work inside and outside home. I want to use my webbrowser like normal please. Please advise.

So reading other threads I need a cert reset or something, can an admin help me or something?

Not trying to snake the thread…Server Version 1.23.4.4805-7000 on DSM7. I cannot connect through browser as well. Plex.tv -->launch

Can I please get some help/