On page you need to click Advanced, Add Exception and then Confirm Security Exception
When I click on Advanced, I have no "Add Exception" button! as you can see on the attachment.
Anyway, my frustrations hit the ceiling yesterday afternoon when my Beelink AP34 miniPC crashed (I suspect overheating) and since then refuses to power up!.
I'll take few days break to figure out how I'll move on from here.
Thanks a lot for your help Vpeter.