This is my 1st login after a fortnight cruising, and as usual I updated the PC with various patches etc, including an update to my Firefox browser, before doing much else. FF now at version 52.0.1. And I got an insecure login warning. Wow!. 1st time I've seen that. So I trapped the imagery, FYI.
here's the actual warning
And here's the explanation (the 'learn more' link in the warning)
I logged in here using the old - potentially insecure - login. The forum admins should review and address this issue which would affect anyone using the FF browser 2nd most popular in the world).
After posting, I tried the suggested https method. Outright failure with that, and this is the message displayed (a bit bigger than needed so that the address bar info can be seen)