X11 forwarding to IP doesn't work on some servers. I can't find any config differences

This command allows me to send an xterm to xming on my windows desktop:

xterm -display 10.13.18.125:0 (my workstation IP)

For the servers that it doesn't work with the IP, It will work for some users to use localhost:10 as the display but if I su to oracle user for example, it doesn't work until I copy my .Xauthority entry to that user.

I'd like to set my display to an IP_address:0 and not mess with xauth. What am I missing?

Thanks.