In order for us to provide better support, we need to see the log generated by Citra. This guide will walk you through how you can obtain the log file: How to Upload the Log File.
Click on ‘UPnP’ and make sure that its enabled (its likely enabled already) make sure to add an exception for citra-qt.exe on your antivirus (including windows defender).
Hopefully I’m not asking a question that sounds either too dumb or condescending, but have you made sure to assign your PC the same static IP address on your local network as you entered in the second field for the virtual server? Your router should have a means of doing so under the DHCP menu.
If you’re not sure which MAC address is yours, you can do the following to find which MAC address(es) are associated with your system:
Press Window + R
Run cmd.exe
Type ipconfig /all
Locate the physical address under the network interface currently in use. If you have already assigned a static IP, this also display the local IP used by your system’s network interface. If it does not match the address assigned, you may need to check your network adapter’s configuration in Windows to ensure it’s not been manually assigned a different IP address than the one desired.
I prefer managing all IP address assignment in the device that handles DHCP (on home networks, a router & on business networks, usually the domain controller or whatever server has been designated to handle it) to avoid the assigning of conflicting addresses which can have the potential to cause other issues.