Did this ever get resolved? I’m having the same problem.
On my MacBook Pro, I was starting the process of upgrading to Cubase 9 and eLicensor read my key. I had a minor issue with download code so I quit the eLicensor while I waited for that to be resolved. Later, when I restarted eLicensor I got the “Lost connection” popups so I upgraded to the latest version and still got them. I downgraded to an even earlier version and it would see my licenses without the problem - for a while. I started getting the problem again. It has always worked on my Surface Pro 3 (USB 3 port). Another odd thing, I have a key from Vienna Instruments and it can be read on either my MBP or SP3 with either version of the eLicensor software - only the Steinberg key seems to have the problem.
This is very discouraging.