I can't read setting in A.
Are you port forwarding on A as 192.168.0.2:5003 to 192.168.0.1:5003?
I found prev thread here Filemaker Server Setting Question
As Wim mentioned there, in A you need forwarding to WAN of B. A can't see anything in LAN of B, so B has setting of forward it.
But I'm not sure it works...
Yes, thats the forwarding from A to B, but it doesnt work because I put the IP address of the Mac Mini which has an IP from B. so I did change the Port forwarding from A to the router IP of B, and still it doesnt work.