Aznkidd235 It is because some router/modem/all-in-one do not support LAN loopback, mostly comcast/xfinity's modem/router do not support LAN loopback service so you'll have to buy your own router that support loopback service to used the WAN IP.
About gameserver
server.property I assume it only support WAN/External IP, hence "
external ip here" which work because my friends are able to connect to it, but not me since my router do not support loopback (xfinity's router do not support loopback).
Wouldn't work with local IP even with port forwarding because I think the
server.property reads it as external only for online, but for offline like usual.