ISTA Connection Difficulty F20 M135i/ENET cable

[BimThereDoneThat]

I have tried with ignition off and on, engine running and not running.
I have Microsoft Visual C++ 2017 (ISTA says it expects 2015 - 2019) and I have tried reinstalling ISTA. Maybe I could try updating my C++ then re-installing ISTA.
Can you offer some hints as to possible network issues? I have given my laptop a fixed address of 169.254.1.1, subnet mask 255.255.0.0 and tried with and without Gateway and DNS addresses of 169.254.0.1. The ENET is at least partly working because ISTA is detecting my VIN.