If you suspect it’s a physical layer issue (cable or port flap) try putting a managed switch in between so that you can see if the port is flapping or there is any sort of physical drop, reset or flap in the connection.

Wouldn’t be the first time a new but dodge cable from China has foiled an otherwise perfect setup.

Yeah good idea.

I'll give that a go and see how I get on.

Hi bickers76,

Did you ever get to the bottom of this? Have exactly the same problem !

Tried with a complete replacement solution even the ISP is different and again the port - which is successfully open simply at a random point in time just Closes.

Driving me nuts too !!!

I have the same issue also, so annoying. Because the Virgin Hub 3 Firmware is probably the worst Router Firmware ever made, it makes it impossible to know what the hell is going on in the network.

I have a Bobcat 300 Miner just installed, I am trying to make sure port 44158 is open. But even after doing Port Forwarding its not open. I've never seen this in all the years I've worked on network switches & routers.

There is no diagnostics so we can see that traffic is being forwarded.