I need to reinstall my softwares on another Mac running MacOS Mojave and I am hitting troubles validating my paid version of LR6. I kept the installers of all my versions of LR (3.0, 5.0, 5.7, 6.0) and started from there. The installation process runs smoothly until it asks to check my product key. I enter it and it then says "please connect to the internet and retry". I am connected to the internet, that is not the issue. If I hit "connect later", it pretends installation is successful, but then when I try to launch LR6, it simultaneously launches Adobe Application Manager and display a "Sign in required" window. I sign in, accept the licence terms, and then comes back the "please connect to the internet to validate your serial number", and LR6 never launches. So it's circular.
I was advised to try the Offline Activation to generate a Request Code, but at no time during the installation process I see the link "I cannot connect to internet" or "Having trouble connecting to the internet", so I am stuck on that side too, I cannot register offline...
Of course my licence is registered on the Adobe website (and LR6 is installed on another of my laptops), this is not the issue either.
Since I also have older versions of LR, I tried to install those and both LR5.0 and LR5.7 installed correctly. Thus the problem is specific to LR6.0.