Thanks for the further screenshots and the make / model of the router
The router is AC1750 Wireless Dual Band Gigabit Router - Model No. Archer C7
You said
When I googled port forward rules for my router is says I would need to create one in the virtual servers tab of the forwarding menu. I never had to do this in the past. There are no port forwarding rules set up in this section. Is this something that is new
This is not new. You decided to tick Manually Specify Port within the Server Remote Access Advanced settings page and if that is ticked, you must have a Port Forward setup - it was always like that. See https://support.plex.tv/articles/200289506-remote-access/
So with the external port entered as 32400 in the manually specify port field, you need to setup a port forward with external/wan/public port 32400 forwarded to internal/lan/private port 32400 and assigned to the local IP address of the server
And with a port forward in place, the local IP of the server must never be changed - so coupled with that you need a DHCP Reservation - which I mentioned before. If you had googled that, you can see the info on how to do it here http://screenshots.portforward.com/routers/TP-Link/Archer_C7/Address_Reservation.htm and on the screenshot you sent to me
you see that there is an
Address Reservation button on the left sidebar within the DHCP section
The alternative to a port forward is to use dynamic port assignment through uPnP, but to do that you need to ensure Manually Specify Port is not ticked when remote access is enabled.
There are pros and cons for the two approaches. A port forward is more reliable but for users that have ISP supplied routers, ISPs sometimes reset the router without any warning or notification and one may find out that all added settings are gone
uPnP dynamic port mapping gets renewed every hour by plex media Server, and we have seen cases where sometimes routers do not respond correctly or timeout and may end up with failures. With uPnP dynamic port mapping you do not need to have a dhcp reservation, however, if the local IP of the server does change, plex apps running on devices and accessing the server locally, may not discover the change immediately and could lead to hiccups. So always best to have a DHCP Reservation or a fixed IP that is static and outside DHCP Range -