Strange Smartlink and router behavior

Dave - WB5NHL

I want to report some strange behavior that might help others.
My network is connected to the internet via an Atlantic Broadband cable modem. The cable modem is a Cisco DPC3827 modem/router. This cable modem enables Upnp by default and I logged into the modem and verified that was enable.
Myself and another Flex owner tested access to my Flex via Smartlink. Below is a summary of results.
1. Remote LAN to my Flex via broadband cable modems - success  (2 different locations)
2. Remote connection via Verizon cellphone hotspot - failure
3. Remote connection via Karma Go hotspot - failure

At this point I was blaming port blocking on the hotspots. As a last thought I tried port forwarding of the Smartlink TCP and UDP ports on my cable modem (Upnp is still enable).

Success on ALL connections!!!!   I do not understand this behavior but everything is working!

Jim Gilliam

Out of curiosity, using your hotspot and Verizon (LTE?) before port forwarding, was the radio discoverable even though you could not establish a connection?

Jim, K6QE

Dave - WB5NHL

Yes, once the email id and password were entered the radio was available. However, the Smartlink test failed and the remote could not connect.