It is not uncommon to have issue accessing a internal server using the external IP.
Normal NAT function the source IP on your packet is translated to the external IP. The issue comes because the destination IP in the packet is also the external IP. So the packet in effect is talking to itself even though it is really 2 differnet internal machines.
The router must have a special feature to support this. This is commonly called hairpin nat but router manufactures tend to not document if the router has this feature or not.
It is somewhat strange you can not access the server using the local IP. That is the normal way to test stuff like this. You can try a simple ping command the local IP but you would have to do something very strange to block traffic between lan devices.
I would suspect it is something related to how the actual server function works. There are some game servers for example you still just have a central matchmaking server and it only has a list of the external IP.
hello when I try pinging it says
ping 192.168.1.4
Pinging 192.168.1.4 with 32 bytes of data:
Reply from 192.168.1.2: Destination host unreachable.
Reply from 192.168.1.2: Destination host unreachable.
Reply from 192.168.1.2: Destination host unreachable.
Reply from 192.168.1.2: Destination host unreachable.
Ping statistics for 192.168.1.4:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
in cmd