Your new NAT router does not support Loopback / Reserve NAT / Hairpin.
I point to pcwintech.com under Routers -> Router Help to where it says How to test if your router supports Reverse NAT.
Please note this assumes that users from the outside can reach your server. If not, make sure:
#1 A Static IP is setup either on the computer or for the computer. Points to portforward.com -> Networking to their Static Vs. Dynamic IP Address guide.
#2 Make sure that you are forwarding correctly.
Two of the most common mistakes are:
a) not fowarding to the correct IP Address.
b) filling in the source port. This needs to be left alone as Any.
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